A partial form of inherited human USP18 deficiency underlies infection and inflammation

International audienceHuman USP18 is an interferon (IFN)-stimulated gene product and a negative regulator of type I IFN (IFN-I) signaling. It also removes covalently linked ISG15 from proteins, in a process called deISGylation. In turn, ISG15 prevents USP18 from being degraded by the proteasome. Autosomal recessive complete USP18 deficiency is life-threatening in infancy owing to uncontrolled IFN-I–mediated autoinflammation. We report three Moroccan siblings with autoinflammation and mycobacterial disease who are homozygous for a new USP18 variant. We demonstrate that the mutant USP18 (p.I60N) is normally stabilized by ISG15 and efficient for deISGylation but interacts poorly with the receptor-anchoring STAT2 and is impaired in negative regulation of IFN-I signaling. We also show that IFN-γ–dependent induction of IL-12 and IL-23 is reduced owing to IFN-I–mediated impairment of myeloid cells to produce both cytokines. Thus, insufficient negative regulation of IFN-I signaling by USP18-I60N underlies a specific type I interferonopathy, which impairs IL-12 and IL-23 production by myeloid cells, thereby explaining predisposition to mycobacterial disease

Systemic Type I IFN Inflammation in Human ISG15 Deficiency Leads to Necrotizing Skin Lesions

Most monogenic disorders have a primary clinical presentation. Inherited ISG15 deficiency, however, has manifested with two distinct presentations to date: susceptibility to mycobacterial disease and intracranial calcifications from hypomorphic interferon-II (IFN-II) production and excessive IFN-I response, respectively. Accordingly, these patients were managed for their infectious and neurologic complications. Herein, we describe five new patients with six novel ISG15 mutations presenting with skin lesions who were managed for dermatologic disease. Cellularly, we denote striking specificity to the IFN-I response, which was previously assumed to be universal. In peripheral blood, myeloid cells display the most robust IFN-I signatures. In the affected skin, IFN-I signaling is observed in the keratinocytes of the epidermis, endothelia, and the monocytes and macrophages of the dermis. These findings define the specific cells causing circulating and dermatologic inflammation and expand the clinical spectrum of ISG15 deficiency to dermatologic presentations as a third phenotype co-dominant to the infectious and neurologic manifestations.Fil: Martin Fernandez, Marta. Icahn School Of Medicine At Mount Sinai; Estados Unidos. King Saud University; Arabia SauditaFil: Bravo García Morato, María. Instituto de Investigacion del Hospital de la Paz.; EspañaFil: Gruber, Conor. Icahn School Of Medicine At Mount Sinai; Estados Unidos. King Saud University; Arabia SauditaFil: Murias Loza, Sara. Instituto de Investigacion del Hospital de la Paz.; EspañaFil: Malik, Muhammad Nasir Hayat. Twincore; Alemania. University Of Lahore; Países Bajos. Leibniz Universitat Hannover; Alemania. Helmholtz Gemeinschaft; AlemaniaFil: Alsohime, Fahad. King Saud University; Arabia SauditaFil: Alakeel, Abdullah. King Saud University; Arabia SauditaFil: Valdez, Rita. Gobierno de la Ciudad Autónoma de Buenos Aires. Hospital General de Agudos Doctor Cosme Argerich; ArgentinaFil: Buta, Sofija. Icahn School Of Medicine At Mount Sinai; Estados UnidosFil: Buda, Guadalupe. Bitgenia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Biología Celular e Histología; ArgentinaFil: Marti, Marcelo Adrian. Bitgenia; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Biología Celular e Histología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Larralde, Margarita. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Ramos Mejía"; ArgentinaFil: Boisson, Bertrand. L'institut Des Maladies Génétiques Imagine; Francia. The Rockefeller University; Estados Unidos. Universite de Paris; FranciaFil: Feito Rodriguez, Marta. Instituto de Investigacion del Hospital de la Paz.; EspañaFil: Qiu, Xueer. Icahn School Of Medicine At Mount Sinai; Estados UnidosFil: Chrabieh, Maya. L'institut Des Maladies Génétiques Imagine; FranciaFil: Al Ayed, Mohammed. Najran University; Arabia SauditaFil: Al Muhsen, Saleh. King Saud University; Arabia SauditaFil: Desai, Jigar V.. National Institutes of Health; Estados UnidosFil: Ferre, Elise M.N.. National Institutes of Health; Estados UnidosFil: Rosenzweig, Sergio D.. National Institutes of Health; Estados UnidosFil: Amador-Borrero, Blanca. Icahn School Of Medicine At Mount Sinai; Estados UnidosFil: Bravo-Gallego, Luz Yadira. Instituto de Investigacion del Hospital de la Paz.; EspañaFil: Olmer, Ruth. Hannover Medical School; Alemania. German Center for Lung Research; AlemaniaFil: Merkert, Sylvia. Hannover Medical School; Alemania. German Center for Lung Research; AlemaniaFil: Bret, Montserrat. Instituto de Investigacion del Hospital de la Paz.; EspañaFil: Sood, Amika K.. University of North Carolina; Estados UnidosFil: Al-rabiaah, Abdulkarim. King Saud University; Arabia SauditaFil: Temsah, Mohamad Hani. King Saud University; Arabia SauditaFil: Halwani, Rabih. University of Sharjah; Emiratos Arabes UnidosFil: Hernandez, Michelle Marilyn. University of North Carolina; Estados UnidosFil: Pessler, Frank. Twincore; Alemania. Helmholtz Centre for Infection Research; AlemaniaFil: Casanova, Jean Laurent. The Rockefeller University; Estados Unidos. Necker Hospital for Sick Children; Francia. Howard Hughes Medical Institute; Estados Unidos. Universite de Paris; FranciaFil: Bustamante, Jacinta. The Rockefeller University; Estados Unidos. Necker Hospital for Sick Children; Francia. Universite de Paris; FranciaFil: Lionakis, Michail S.. National Institutes of Health; Estados UnidosFil: Bogunovic, Dusan. Icahn School Of Medicine At Mount Sinai; Estados Unido

An ACE2 Triple Decoy that neutralizes SARS-CoV-2 shows enhanced affinity for virus variants

Abstract The SARS-CoV-2 variants replacing the first wave strain pose an increased threat by their potential ability to escape pre-existing humoral protection. An angiotensin converting enzyme 2 (ACE2) decoy that competes with endogenous ACE2 for binding of the SARS-CoV-2 spike receptor binding domain (S RBD) and inhibits infection may offer a therapeutic option with sustained efficacy against variants. Here, we used Molecular Dynamics (MD) simulation to predict ACE2 sequence substitutions that might increase its affinity for S RBD and screened candidate ACE2 decoys in vitro. The lead ACE2(T27Y/H34A)-IgG1FC fusion protein with enhanced S RBD affinity shows greater live SARS-CoV-2 virus neutralization capability than wild type ACE2. MD simulation was used to predict the effects of S RBD variant mutations on decoy affinity that was then confirmed by testing of an ACE2 Triple Decoy that included an additional enzyme activity-deactivating H374N substitution against mutated S RBD. The ACE2 Triple Decoy maintains high affinity for mutated S RBD, displays enhanced affinity for S RBD N501Y or L452R, and has the highest affinity for S RBD with both E484K and N501Y mutations, making it a viable therapeutic option for the prevention or treatment of SARS-CoV-2 infection with a high likelihood of efficacy against variants

Human TBK1 deficiency leads to autoinflammation driven by TNF-induced cell death

TANK binding kinase 1 (TBK1) regulates IFN-I, NF-κB, and TNF-induced RIPK1-dependent cell death (RCD). In mice, biallelic loss of TBK1 is embryonically lethal. We discovered four humans, ages 32, 26, 7, and 8 from three unrelated consanguineous families with homozygous loss-of-function mutations in TBK1. All four patients suffer from chronic and systemic autoinflammation, but not severe viral infections. We demonstrate that TBK1 loss results in hypomorphic but sufficient IFN-I induction via RIG-I/MDA5, while the system retains near intact IL-6 induction through NF-κB. Autoinflammation is driven by TNF-induced RCD as patient-derived fibroblasts experienced higher rates of necroptosis in vitro, and CC3 was elevated in peripheral blood ex vivo. Treatment with anti-TNF dampened the baseline circulating inflammatory profile and ameliorated the clinical condition in vivo. These findings highlight the plasticity of the IFN-I response and underscore a cardinal role for TBK1 in the regulation of RCD

Human USP18 deficiency underlies type 1 interferonopathy leading to severe pseudo-TORCH syndrome

Pseudo-TORCH syndrome (PTS) is characterized by microcephaly, enlarged ventricles, cerebral calcification, and, occasionally, by systemic features at birth resembling the sequelae of congenital infection but in the absence of an infectious agent. Genetic defects resulting in activation of type 1 interferon (IFN) responses have been documented to cause Aicardi-Goutières syndrome, which is a cause of PTS. Ubiquitin-specific peptidase 18 (USP18) is a key negative regulator of type I IFN signaling. In this study, we identified loss-of-function recessive mutations of USP18 in five PTS patients from two unrelated families. Ex vivo brain autopsy material demonstrated innate immune inflammation with calcification and polymicrogyria. In vitro, patient fibroblasts displayed severely enhanced IFN-induced inflammation, which was completely rescued by lentiviral transduction of USP18. These findings add USP18 deficiency to the list of genetic disorders collectively termed type I interferonopathies. Moreover, USP18 deficiency represents the first genetic disorder of PTS caused by dysregulation of the response to type I IFNs. Therapeutically, this places USP18 as a promising target not only for genetic but also acquired IFN-mediated CNS disorders