Molluscum Contagiosum Virus Research Articles

Molluscum contagiosum virus protein MC089 inhibits interferon regulatory factor 3 activation.

Molluscum contagiosum virus (MCV) is a human-specific poxvirus that causes a highly common but mild infection characterized by distinctive and persistent papular skin lesions. These lesions can persist for long periods without an effective clearance response from the host. MCV, like all poxviruses, encodes multiple known immunosuppressive proteins which target innate immune signalling pathways involved in viral nucleic acid sensing, interferon production and inflammation which should trigger antiviral immunity leading to clearance. Two major families of transcription factors responsible for driving the immune response to viruses are the NF-κB and the interferon regulatory factor (IRF) families. While NF-κB broadly drives pro-inflammatory gene expression and IRFs chiefly drive interferon induction, both collaborate in transactivating many of the same genes in a concerted immune response to viral infection. Here, we report that the MCV protein MC089 specifically inhibits IRF activation from both DNA- and RNA-sensing pathways, making it the first characterized MCV inhibitor to selectively target IRF activation to date. MC089 interacts with proteins required for IRF activation, namely IKKε, TBKBP1 and NAP1. Additionally, MC089 targets RNA sensing by associating with the RNA-sensing adaptor protein mitochondrial antiviral-signalling protein on mitochondria. MC089 displays specificity in its inhibition of IRF3 activation by suppressing immunostimulatory nucleic acid-induced serine 396 phosphorylation without affecting the phosphorylation of serine 386. The selective interaction of MC089 with IRF-regulatory proteins and site-specific inhibition of IRF3 phosphorylation may offer a tool to provide novel insights into the biology of IRF3 regulation.

Cutaneous infections in Atopic Dermatitis (AD) – a literature review

Atopic dermatitis (AD) is a chronic inflammatory disease that affects people of all ages, usually with onset in childhood. It is a multifactorial, complex disorder that causes disruption of the skin barrier and is associated with an abnormal immune response that can predispose to both cutaneous and extracutaneous infections with the potential to become systemic infections. The aim of this article is to present cutaneous infections as the most common complications of atopic dermatitis (AD). Atopic dermatitis (AD) increases susceptibility to skin viral and bacterial infections. These include Staphylococcus aureus colonization, molluscum contagiosum (MC), eczema herpeticum (EH) and human papilloma virus (HPV) infection. Among them, Staphylococcus aureus infection is the most frequently observed. Molluscum contagiosum (MC) and AD are considered risk factors for each other. However, studies on the relationship between MC and AD are divergent and there is a need for further research. Eczema herpeticum and systemic infections can be life-threatening nevertheless they are not common. Individuals with AD are more prone to HPV infections with various subtypes. Research shows that AD increases the risk of cervical cancer. Cutaneous infections are the most common complication of atopic dermatitis (AD) and are associated with various health risks. Preventive therapy in AD emphasizes improving the skin barrier. Early recognition of skin infections and introduction of adequate therapy is important to prevent serious medical complications. Keywords: Staphylococcus aureus, Eczema Herpeticum, HPV, Molluscum Contagiosum.

A novel digital PCR assay for detection and comprehensive characterization of Molluscum contagiosum virus genotypes MOCV1, MOCV2, and MOCV3 and recombinant lineages

Molluscum contagiosum virus (MOCV) is an important human pathogen causing a high disease burden worldwide. It is the last exclusively human-infecting poxvirus still circulating in its natural reservoir—a valuable model of poxviral evolution. Unfortunately, MOCV remains neglected, and little is known about its evolutionary history and circulating genomic variants, especially in non-privileged countries. The design weaknesses of available MOCV detection/genotyping assays surfaced with recent accumulation of abundant sequence information: all existing MOCV assays fail at accurate genotyping and capturing sub-genotype level diversity. Because complete MOCV genome characterization is an expensive and labor-intensive task, it makes sense to prioritize samples for whole-genome sequencing by diversity triage screening. To meet this demand, we developed a novel assay for accurate MOCV detection and genotyping, and comprehensive sub-genotype qualification to the level of phylogenetic groups (PGs). The assay included a novel set of oligonucleotide primers and probes, and it was implemented using digital polymerase chain reaction (dPCR). It offers sensitive, specific, and accurate detection, genotyping (MOCV1–MOCV3), and PG qualification (PG1–6) of MOCV DNA from clinical samples. The novel dPCR assay is suitable for MOCV diversity triage screening and prioritization of samples for complete MOCV genome characterization.

Differential diagnosis of exanthematous viruses during the 2022 Mpox outbreak in Minas Gerais, Brazil.

Brazil ranks second in the number of cases during the global monkeypox epidemic. The study, conducted in Minas Gerais, the second most populous state in Brazil with over 20 million inhabitants, utilized differential diagnostics, revealing a significant number of positive cases for other exanthematous viruses and emphasizing the need for accurate diagnoses. During the study, we were able to assess the co-circulation of other viruses alongside monkeypox, including varicella-zoster virus, molluscum contagiosum virus, and other orthopoxviruses. The significance of the research is underscored by the concentration of positive cases in populous areas, highlighting the challenges posed by emerging infectious diseases. This demographic context further amplifies the importance of the research in guiding public health policies and medical interventions, given the substantial population at risk. The study not only addresses a global concern but also holds critical implications for a state with such a large population and geographic expanse within Brazil. Overall, the study emphasizes the pivotal role of surveillance and precise diagnosis in guiding effective public health responses and ensuring appropriate medical interventions.

Molecular epidemiology and histopathology study of molluscum contagious virus in patients with clinical lesions in Al-Qadisiyah province, Iraq

BackgroundMolluscum contagiosum virus (MCV) is a viral cutaneous infection that occasionally affects the mucous membrane and skin, mainly among children and young adults, occurring worldwide. MCV is a double-stranded DNA virus that belongs to the poxvirus family. The prevalence of MCV in Iraq and its frequency are mostly unknown, despite the virus being transmissible directly from person to person, with several significant outbreaks reported in recent years. This study represents the first investigation of MCV in the province of Al-Qadisiyah. Utilizing real-time PCR and histopathological examination, the research aimed to validate the clinical diagnosis of MCV. The study involved the histological examination of Molluscum contagiosum and compared it with real-time PCR analysis of MCV. MethodsThe study was conducted from October 1, 2022, to March 30, 2023. Lesion samples were taken from 80 patients initially. The disease had spread widely and quickly in the city, affecting individuals aged between 1 and 2 years who had been diagnosed with clinical lesions of MCV on various body areas. Non-random (purposive) samples were collected for the study. ResultsFollowing real-time PCR testing and histological examination (90 %), patients yielded positive results for Molluscum contagiosum virus (MCV), aligning with clinical diagnosis. Histopathological analysis revealed distinctive cytopathic effects and localized hyperplasia in epidermal keratinocytes indicative of Molluscum contagiosum. No significant disparity was observed between MCV infection and sex or age. Additionally, histological examination identified 8 (10 %) patients infected with human papillomaviruses. ConclusionThe present comprehension regarding the epidemiology and prevalence of MCV in Iraq remains limited. The findings highlight a significant rise in MCV infections compared to other infectious skin diseases, underscoring the urgency for further investigation to mitigate the risk of a potential global epidemic.

Potency of a small molecule that targets the molluscum contagiosum virus processivity factor increases when conjugated to a tripeptide

We recently developed compound FC-7269 for targeting the Molluscum contagiosum virus processivity factor (mD4) and demonstrated its ability to inhibit viral processive DNA synthesis in vitro and cellular infection of an mD4-dependent virus (Antiviral Res 211, 2023,105520). However, despite a thorough medicinal chemistry campaign we were unable to generate a potent second analog as a requisite for drug development. We overcame this impasse, by conjugating a short hydrophobic trivaline peptide to FC-7269 to produce FC-TriVal-7269 which significantly increased antiviral potency and reduced cellular toxicity.

Molluscum Contagiosum Profile At The Dermatology And Venereology Polyclinic Of Prof. I.G.N.G. Ngoerah Central General Hospital Denpasar

Molluscum contagiosum (MC) is a viral infectious disease caused by the Molluscum Contagiosum Virus (MCV). There are four subtypes of MCV (MCV-1, MCV-2, MCV-3, and MCV-4). The worldwide incidence of MK infection is estimated to be around 2% to 8%, while in the HIV/AIDS population, it is approximately 5% to 18%. To date, there is limited research reporting on the profile of MC patients in Indonesia. This is a descriptive cross-sectional research design. Data were obtained retrospectively and collected from the medical records of patients with molluscum contagiosum who visited the Dermatology and Venereology Polyclinic at Prof. I.G.N.G. Ngoerah General Hospital in Denpasar, Bali, from January 2018 to December 2020. In this study of molluscum contagiosum infection at the Dermatology and Venereology Polyclinic of Sanglah General Hospital in Denpasar, Bali, during the period of January 2018 to December 2020, the majority of participants were aged between 18-44 years (61.1%) and were male (61.1%). Most participants were from Bali (77.8%) and were married (55.6%). Moreover, the majority of participants were sexually active (77.8%) and had a negative HIV status (55.6%). Concerning sexual orientation, most participants identified as heterosexual (83.3%). Regarding the type of therapy received, most participants underwent enucleation (55.5%) and combination therapy (22.2%). Broad public education, especially for parents, regarding molluscum contagiosum should be enhanced to support more effective healthcare efforts encompassing treatment, prevention, and health promotion.

β-Actin G342D as a Cause of NK Cell Deficiency Impairing Lytic Synapse Termination.

NK cell deficiency (NKD) occurs when an individual's major clinical immunodeficiency derives from abnormal NK cells and is associated with several genetic etiologies. Three categories of β-actin-related diseases with over 60 ACTB (β-actin) variants have previously been identified, none with a distinct NK cell phenotype. An individual with mild developmental delay, macrothrombocytopenia, and susceptibility to infections, molluscum contagiosum virus, and EBV-associated lymphoma had functional NKD for over a decade. A de novo ACTB variant encoding G342D β-actin was identified and was consistent with the individual's developmental and platelet phenotype. This novel variant also was found to have direct impact in NK cells because its expression in the human NK cell line YTS (YTS-NKD) caused increased cell spreading in lytic immune synapses created on activating surfaces. YTS-NKD cells were able to degranulate and perform cytotoxicity, but they demonstrated defective serial killing because of prolonged conjugation to the killed target cell and thus were effectively unable to terminate lytic synapses. G342D β-actin results in a novel, to our knowledge, mechanism of functional NKD via increased synaptic spreading and defective lytic synapse termination with resulting impaired serial killing, leading to overall reductions in NK cell cytotoxicity.

Molluscum Contagiosum Virus: Biology and Immune Response.

Molluscum contagiosumvirus is a poxvirus belonging to the Poxviridae family, which includes Orthopoxvirus, Parapoxvirus, Yantapoxvirus, Molluscipoxvirus, Smallpox virus, Cowpox virus and Monkeypox virus. MCVbelongs to the genus Molluscipoxvirus and has a tropism for skin tissue. MCV infects keratinocytes and, after an incubation period of 2 weeks to 6 weeks, causes a breakdown of the skin barrier with the development of papules of variable size depending on the proper functioning of the immune response (both adaptive and acquired). MCV only infects humans and does not cause viraemia. MCV encodes for several inhibitory proteins responsible to circumvent the immune response through different signalling pathways. Individuals who can be infected with MCV are children, immunocompromised individuals such as organ transplant recipients and Human Immunodeficiency Virus (HIV)-infected individuals. Current treatments to manage MCV-induced lesions are different and include the use of immunomodulators, which, however, do not provide an effective response.

Poxvirus infections in dermatology - the neglected, the notable, and the notorious.

The family Poxviridae currently comprises 22 genera that infect vertebrates. Of these, members of the Ortho-, Para-, Mollusci- and Yatapoxvirus genera have been associated with human diseases of high clinical relevance in dermatology. Historically, smallpox had been a notorious health threat until it was declared eradicated by the World Health Organization in 1979. Today, dermatologists are confronted with a variety of poxviral infections, such as farmyard pox, which occurs as a zoonotic infection after contact with animals. In the tropics, tanapox or vaccinia may be in the differential diagnosis as neglected tropical dermatoses. Molluscum contagiosum virus infection accounts for significant disease burden worldwide and is classified as a sexually transmitted infection in certain scenarios. Recently, mpox (monkeypox) has emerged as a public health emergency of international concern, requiring rapid recognition and appropriate management by dermatologists and infectious disease specialists. Advances and new insights into the epidemiology, diagnosis, clinical manifestations and complications, treatment, and prevention of poxviral infections require a high level of expertise and interdisciplinary skills from healthcare professionals linking virology, infectious diseases, and dermatology. This CME article provides a systematic overview and update to assist the practicing dermatologist in the identification, differential diagnosis, and management of poxviral infections.

Comprehensive analysis of 66 complete molluscum contagiosum virus (MOCV) genomes: characterization and functional annotation of 47 novel complete MOCV genomes, including the first genome of MOCV genotype 3, and a proposal for harmonized MOCV genotyping indexing.

Four molluscum contagiosum virus (MOCV) genotypes (MOCV1-4) and four subtype variants were partially characterized using restriction enzyme profiling in the 1980s/1990s, but complete genome sequences of only MOCV1 and MOCV2 are available. The evolutionary pathways whereby genotypes/subtype variants with unavailable sequences emerged and whether all MOCVs can be detected using current diagnostic approaches remain unclear. We fully characterized 47 novel complete MOCV genomes, including the first complete MOCV3 genome, expanding the number of fully characterized genomes to 66. For reliably classifying the novel non-MOCV1/2 genomes, we developed and validated a framework for matching sequence-derived restriction maps with those defining MOCV subtypes in pioneering studies. Six phylogenetic subgroups (PG1-6) were identified, PG5 representing a novel MOCV2 subtype. The phylogenetic subgroups diverged from the prototype lineages following large-scale recombination events and hinted at partial sequence content of MOCV4 and direction of recombinant transfer in the events spawning PG5 and yet undetected MOCV1vb variant.

The MC160 protein of the molluscum contagiosum virus dampens cGAS/STING-induced interferon-β activation

Molluscum contagiosum virus (MCV) is a poxvirus that causes benign, persistent skin lesions. MCV encodes a variety of immune evasion molecules to dampen host immune responses. Two of these proteins are the MC159 and MC160 proteins. Both MC159 and MC160 contain two tandem death effector domains and share homology to the cellular FLIPs, FADD, and procaspase-8. MC159 and MC160 dampen several innate immune responses such as NF-κB activation and mitochondrial antiviral signaling (MAVS)-mediated induction of type 1 interferon (IFN). The type 1 IFN response is also activated by the cytosolic DNA sensors cyclic GMP-AMP synthase (cGAS) and stimulator of interferon genes (STING). Both cGAS and STING play a vital role in sensing a poxvirus infection. In this study, we demonstrate that there are nuanced differences between both MC160 and MC159 in terms of how the viral proteins modulate the cGAS/STING and MAVS pathways. Specifically, MC160 expression, but not MC159 expression, dampens cGAS/STING-mediated induction of IFN in HEK 293 T cells. Further, MC160 expression prevented the K63-ubiquitination of both STING and TBK1, a kinase downstream of cGAS/STING. Ectopic expression of the MC160 protein, but not the MC159 protein, resulted in a measurable decrease in the TBK1 protein levels as detected via immunoblotting. Finally, using a panel of MC160 truncation mutants, we report that the MC160 protein requires both DEDs to inhibit cGAS/STING-induced activation of IFN-β. Our model indicates MC160 likely alters the TBK1 signaling complex to decrease IFN-β activation at the molecular intersection of the cGAS/STING and MAVS signaling pathways.

Unveiling Hidden Risks: Intentional Molecular Screening for Sexually Transmitted Infections and Vaginosis Pathogens in Patients Who Have Been Exclusively Tested for Human Papillomavirus Genotyping.

This analytical, prospective, cross-sectional study included 408 males and females. Eligible participants had positive and negative HPV genotyping test results and agreed to early detection or had HPV antecedents. They provided the same urogenital samples used for HPV detection and, through our multiplex in-house PCR assay, we screened for Candida spp., Ureaplasma spp., Trichomonas vaginalis, Neisseria gonorrhoeae, Chlamydia trachomatis, herpes simplex virus 1 and 2 (HSV), Mycoplasma spp., molluscum contagiosum virus (MCV), Treponema pallidum, Haemophilus spp., Staphylococcus aureus, and Klebsiella spp. The subsequent statistical analysis aimed to reveal correlations between HPV genotypes and the identified pathogens. Of the participants, 72.1% (n = 294) tested positive for HPV genotypes. HR-HPV (high-risk HPV) genotypes comprised 51 (8.1%), 66 (7.1%), and 58 (6.1%). Haemophilus spp., Ureaplasma spp., Candida spp., Staphylococcus aureus, and Mycoplasma spp. frequently co-occurred with HPV infection (p < 0.05). Gender-based variations were notorious for Ureaplasma spp., Mycoplasma spp., and MCV (p < 0.05). Coinfections were prevalent (43.9%), with a positive HPV result elevating the risk for Trichomonas vaginalis, Mycoplasma spp., Staphylococcus aureus, HSV, and MCV (OR > 1, p < 0.05). HPV 16 correlated with HSV and Ureaplasma spp., while HPV 6 was linked with HSV and MCV (p < 0.05). This screening strategy uncovered significant coinfections and associations between HPV genotypes and pathogens, underscoring the importance of routine screening to explore clinical implications in urogenital health.

History of S. aureus Skin Infection Significantly Associates with History of Eczema Herpeticum in Patients with Atopic Dermatitis.

Patients with atopic dermatitis (AD) are uniquely susceptible to a number of serious viral skin complications, including eczema herpeticum (EH), caused by herpes simplex virus. This study explored the associations between biomarkers of epithelial barrier dysfunction, type 2 immunity, Staphylococcus aureus infection, and S. aureus-specific immunoglobulin responses in a cohort of AD subjects with and without a history of EH (EH+ and EH-, respectively). A total of 112 subjects with AD (56 EH+, 56 EH-), matched by age and AD severity, were selected from a registry of over 3000 AD subjects. Logistic regression was used to test the association between history of S. aureus skin infection and history of EH, while controlling for a number of confounders. Compared to those without a history of S. aureus skin infection, subjects with a history of S. aureus skin infection were found to have more than sixfold increased odds of having a history of EH (6.60, 95% confidence interval [CI]: 2.00-21.83), after adjusting for history of other viral skin infections (molluscum contagiosum virus, human papillomavirus), serum total IgE, and IgG against the S. aureus virulence factor SElX. These findings indicate an important relationship between S. aureus skin infections and EH.

Laboratory assessment of a multi-target assay for the rapid detection of viruses causing vesicular diseases.

The recent mpox outbreak has highlighted the need to rapidly diagnose the causative agents of viral vesicular disease to inform treatment and control measures. Common causes of vesicular disease include Monkeypox virus (MPXV), clades I and II, Herpes simplex viruses Type 1 and Type 2 (HSV-1, HSV-2), human herpes virus 6 (HHV-6), Varicella-zoster virus (VZV) and Enteroviruses (EVs). Here, we assessed a syndromic viral vesicular panel for rapid and simultaneous detection of these 7 targets in a single cartridge. The aim of this study was to evaluate the QIAStat-Dx ® viral vesicular (VV) panel and compare with laboratory developed tests (LDTs). Limit of detection, inter-run variability, cross-reactivity and specificity were assessed. Positive and negative percent agreement, and correlation between assays was determined using 124 clinical samples from multiple anatomical sites. The overall concordance between the QIAstat and LDTs was 96%. Positive percent agreement was 82% for HHV-6, 89% for HSV-1 and 100% for MPXV, HSV-2, EV and VZV. Negative percent agreement was 100% for all targets assessed. There was no cross-reactivity with Vaccinia, Orf, Molluscum contagiosum viruses, and a pooled respiratory panel. The QIAstat VV multi-target syndromic panel combine ease of use, rapid turnaround, good sensitivity and specificity for enhanced diagnosis, clinical care and public health responses.

Phenotypic and Endotypic Determinants of Atopic Dermatitis Severity From the Atopic Dermatitis Research Network (ADRN) Registry.

Atopic dermatitis (AD) is a chronic inflammatory skin condition with a highly variable clinical phenotype. This study aimed to identify historical and clinical features and biomarkers associated with AD severity. A US registry of extensively phenotyped AD participants (aged 0.73-80 years) were enrolled at 9 academic centers. Information on family and personal medical history, examination, skin swabs (culture), and serum biomarkers was collected to evaluate their association with AD severity. Participants with AD (N= 2862) whose disease was categorized as mild (11.6%), moderate (58.0%), or severe (30.4%) based on Rajka-Langeland scoring were enrolled. The trend test, when adjusting for gender, race, and age, demonstrated that severity was strongly (P ≤ .04) associated with a personal/family history of allergic disorders, history of alopecia, exposure to passive smoke, ocular herpes infection, skin bacterial and viral infections, and history of arrhythmia. Features observed more frequently (P ≤ .002), as a function of severity, included skin infections (impetigo, human papillomavirus, and molluscum contagiosum virus), Staphylococcus aureus colonization, excoriations, hyperlinear palms, ichthyosis, blepharitis, conjunctivitis, ectropion, and wheezing. Serum IgE, allergen and food (≤6 years) Phadiatop, and eosinophilia were strongly linked to severity (P < .001). In a diverse US AD population, severity was associated with a history of atopic disorders, skin and extracutaneous bacterial and viral infections (by history and physical examination), higher IgE, eosinophilia and allergen sensitization, atopic skin manifestations (ie, excoriation, hyperlinear palms, and ichthyosis), and atopic ocular features (ie, blepharitis, conjunctivitis, and ectropion) as well as asthma findings (ie, wheezing). Data from our prospective registry significantly advance our understanding of AD phenotypes and endotypes, which is critical to achieve optimal management.

Occurrences of similar viral diversity in campus wastewater and reclaimed water of a university dormitory

Water reuse from wastewater sources still remain some critical safety concerns associated with treacherous contaminants like pathogenic viruses. In this study, viral diversities in campus wastewater (CWW) and its reclaimed water (RCW) recycled for toilet flushing and garden irrigation of a university dormitory were assessed using metagenomic sequencing for acquisition of more background data. Results suggested majority (>80%) of gene sequences within assembled contigs predicted by open reading frame (ORF) finder were no-hit yet believed to be novel/unrevealed viral genomic information whereas hits matched bacteriophages (i.e., mainly Myoviridae, Podoviridae, and Siphoviridae families) were predominant in both CWW and RCW samples. Moreover, few pathogenic viruses (<1%) related to infections of human skin (e.g., Molluscum contagiosum virus, MCV), digestion system (e.g., hepatitis C virus, HCV), and gastrointestinal tract (e.g., human norovirus, HuNoV) were also noticed raising safety concerns about application of reclaimed waters. Low-affinity interactions of particular viral exterior proteins (e.g., envelope glycoproteins or spike proteins) for disinfectant ligand (e.g., chlorite) elucidated treatment limitations of current sewage processing systems even with membrane bioreactor and disinfectant contactor. Revolutionary disinfection approaches together with routine monitoring and new regulations are prerequisite to secure pathogen-correlated water quality for safer reuse of reclaimed waters.

Molluscum Contagiosum Virus Protein MC008 Targets NF-κB Activation by Inhibiting Ubiquitination of NEMO.

Molluscum contagiosum virus (MCV) is a human-adapted poxvirus that causes a common and persistent yet mild infection characterized by distinct, contagious, papular skin lesions. These lesions are notable for having little or no inflammation associated with them and can persist for long periods without an effective clearance response from the host. Like all poxviruses, MCV encodes potent immunosuppressive proteins that perturb innate immune pathways involved in virus sensing, the interferon response, and inflammation, which collectively orchestrate antiviral immunity and clearance, with several of these pathways converging at common signaling nodes. One such node is the regulator of canonical nuclear factor kappa B (NF-κB) activation, NF-κB essential modulator (NEMO). Here, we report that the MCV protein MC008 specifically inhibits NF-κB through its interaction with NEMO, disrupting its early ubiquitin-mediated activation and subsequent downstream signaling. MC008 is the third NEMO-targeting inhibitor to be described in MCV to date, with each inhibiting NEMO activation in distinct ways, highlighting strong selective pressure to evolve multiple ways of disabling this key signaling protein. IMPORTANCE Inflammation lies at the heart of most human diseases. Understanding the pathways that drive this response is the key to new anti-inflammatory therapies. Viruses evolve to target inflammation; thus, understanding how they do this reveals how inflammation is controlled and, potentially, how to disable it when it drives disease. Molluscum contagiosum virus (MCV) has specifically evolved to infect humans and displays an unprecedented ability to suppress inflammation in our tissue. We have identified a novel inhibitor of human innate signaling from MCV, MC008, which targets NEMO, a core regulator of proinflammatory signaling. Furthermore, MC008 appears to inhibit early ubiquitination, thus interrupting later events in NEMO activation, thereby validating current models of IκB kinase (IKK) complex regulation.

Therapeutic strategies for human poxvirus infections: Monkeypox (mpox), smallpox, molluscipox, and orf.

Therapeutic and vaccine development for human poxvirus infections (e.g., monkeypox (mpox) virus, variola virus, molluscum contagiosum virus, orf virus) has been largely deserted, especially after the eradication of smallpox by 1980. Human mpox is a self-limited disease confined to Central and West Africa for decades. However, since April 2022, mpox has quickly emerged as a multi-country outbreak, urgently calling for effective antiviral agents and vaccines to control mpox. Here, this review highlights possible therapeutic options (e.g., tecovirimat, brincidofovir, cidofovir) and other strategies (e.g., vaccines, intravenous vaccinia immune globulin) for the management of human poxvirus infections worldwide.

CRISPR screens identify novel regulators of cFLIP dependency and ligand-independent, TRAIL-R1-mediated cell death.

Kaposi's sarcoma-associated herpesvirus (KSHV) causes primary effusion lymphoma (PEL). PEL cell lines require expression of the cellular FLICE inhibitory protein (cFLIP) for survival, although KSHV encodes a viral homolog of this protein (vFLIP). Cellular and viral FLIP proteins have several functions, including, most importantly, the inhibition of pro-apoptotic caspase 8 and modulation of NF-κB signaling. To investigate the essential role of cFLIP and its potential redundancy with vFLIP in PEL cells, we first performed rescue experiments with human or viral FLIP proteins known to affect FLIP target pathways differently. The long and short isoforms of cFLIP and molluscum contagiosum virus MC159L, which are all strong caspase 8 inhibitors, efficiently rescued the loss of endogenous cFLIP activity in PEL cells. KSHV vFLIP was unable to fully rescue the loss of endogenous cFLIP and is therefore functionally distinct. Next, we employed genome-wide CRISPR/Cas9 synthetic rescue screens to identify loss of function perturbations that can compensate for cFLIP knockout. Results from these screens and our validation experiments implicate the canonical cFLIP target caspase 8 and TRAIL receptor 1 (TRAIL-R1 or TNFRSF10A) in promoting constitutive death signaling in PEL cells. However, this process was independent of TRAIL receptor 2 or TRAIL, the latter of which is not detectable in PEL cell cultures. The requirement for cFLIP is also overcome by inactivation of the ER/Golgi resident chondroitin sulfate proteoglycan synthesis and UFMylation pathways, Jagunal homolog 1 (JAGN1) or CXCR4. UFMylation and JAGN1, but not chondroitin sulfate proteoglycan synthesis or CXCR4, contribute to TRAIL-R1 expression. In sum, our work shows that cFLIP is required in PEL cells to inhibit ligand-independent TRAIL-R1 cell death signaling downstream of a complex set of ER/Golgi-associated processes that have not previously been implicated in cFLIP or TRAIL-R1 function.