The efficacy of immune checkpoint inhibitors (ICIs) in patients with advanced melanomathat develop brain metastases (BM) remains unpredictable. In this study, we aimed to identifyprognostic factors... Show moreThe efficacy of immune checkpoint inhibitors (ICIs) in patients with advanced melanomathat develop brain metastases (BM) remains unpredictable. In this study, we aimed to identifyprognostic factors in patients with melanoma BM who are treated with ICIs. Data from advancedmelanoma patients with BM treated with ICIs in any line between 2013 and 2020 were obtained fromthe Dutch Melanoma Treatment Registry. Patients were included from the time of the treatment ofBM with ICIs. Survival tree analysis was performed with clinicopathological parameters as potentialclassifiers and overall survival (OS) as the response variable. In total, 1278 patients were included.Most patients were treated with ipilimumab–nivolumab combination therapy (45%). The survivaltree analysis resulted in 31 subgroups. The median OS ranged from 2.7 months to 35.7 months. Thestrongest clinical parameter associated with survival in advanced melanoma patients with BM wasthe serum lactate dehydrogenase (LDH) level. Patients with elevated LDH levels and symptomaticBM had the worst prognosis. The clinicopathological classifiers identified in this study can contributeto optimizing clinical studies and can aid doctors in giving an indication of the patients’ survivalbased on their baseline and disease characteristics. Show less
Apart from prevention using vaccinations, the management options for COVID-19 remain limited. In retrospective cohort studies, use of famotidine, a specific oral H2 receptor antagonist ... Show moreApart from prevention using vaccinations, the management options for COVID-19 remain limited. In retrospective cohort studies, use of famotidine, a specific oral H2 receptor antagonist (antihistamine), has been associated with reduced risk of intubation and death in patients hospitalized with COVID-19. In a case series, nonhospitalized patients with COVID-19 experienced rapid symptom resolution after taking famotidine, but the molecular basis of these observations remains elusive. Here we show using biochemical, cellular, and functional assays that famotidine has no effect on viral replication or viral protease activity. However, famotidine can affect histamine-induced signaling processes in infected Caco2 cells. Specifically, famotidine treatment inhibits histamine-induced expression of Toll-like receptor 3 (TLR3) in SARS-CoV-2 infected cells and can reduce TLR3-dependent signaling processes that culminate in activation of IRF3 and the NF-kappa B pathway, subsequently controlling antiviral and inflammatory responses. SARS-CoV-2-infected cells treated with famotidine demonstrate reduced expression levels of the inflammatory mediators CCL-2 and IL6, drivers of the cytokine release syndrome that precipitates poor outcome for patients with COVID-19. Given that pharmacokinetic studies indicate that famotidine can reach concentrations in blood that suffice to antagonize histamine H2 receptors expressed in mast cells, neutrophils, and eosinophils, these observations explain how famotidine may contribute to the reduced histamine-induced inflammation and cytokine release, thereby improving the outcome for patients with COVID-19. Show less
Legionella pneumophila causes a severe pneumonia known as Legionnaires' disease. During the infection, Legionella injects more than 300 effector proteins into host cells. Among them are enzymes... Show moreLegionella pneumophila causes a severe pneumonia known as Legionnaires' disease. During the infection, Legionella injects more than 300 effector proteins into host cells. Among them are enzymes involved in altering the host-ubiquitination system. Here, we identified two LegionellaOTU (ovarian tumor)-like deubiquitinases (LOT-DUBs; LotB [Lpg1621/Ceg23] and LotC [Lpg2529]). The crystal structure of the LotC catalytic core (LotC(14-310)) was determined at 2.4 angstrom. Unlike the classical OTU-family, the LOT-family shows an extended helical lobe between the Cysloop and the variable loop, which defines them as a unique class of OTU-DUBs. LotB has an additional ubiquitin-binding site (S1'), which enables the specific cleavage of Lys63-linked polyubiquitin chains. By contrast, LotC only contains the S1 site and cleaves different species of ubiquitin chains. MS analysis of LotB and LotC identified different categories of host-interacting proteins and substrates. Together, our results provide new structural insights into bacterial OTU-DUBs and indicate distinct roles in host-pathogen interactions. Show less
Biochemical, structural and functional studies on the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) papain-like protease PLpro reveal that it regulates host antiviral responses by... Show moreBiochemical, structural and functional studies on the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) papain-like protease PLpro reveal that it regulates host antiviral responses by preferentially cleaving the ubiquitin-like interferon-stimulated gene 15 protein (ISG15) and identify this protease as a potential therapeutic target for coronavirus disease 2019 (COVID-19).The papain-like protease PLpro is an essential coronavirus enzyme that is required for processing viral polyproteins to generate a functional replicase complex and enable viral spread(1,2). PLpro is also implicated in cleaving proteinaceous post-translational modifications on host proteins as an evasion mechanism against host antiviral immune responses(3-5). Here we perform biochemical, structural and functional characterization of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) PLpro (SCoV2-PLpro) and outline differences with SARS-CoV PLpro (SCoV-PLpro) in regulation of host interferon and NF-kappa B pathways. SCoV2-PLpro and SCoV-PLpro share 83% sequence identity but exhibit different host substrate preferences; SCoV2-PLpro preferentially cleaves the ubiquitin-like interferon-stimulated gene 15 protein (ISG15), whereas SCoV-PLpro predominantly targets ubiquitin chains. The crystal structure of SCoV2-PLpro in complex with ISG15 reveals distinctive interactions with the amino-terminal ubiquitin-like domain of ISG15, highlighting the high affinity and specificity of these interactions. Furthermore, upon infection, SCoV2-PLpro contributes to the cleavage of ISG15 from interferon responsive factor 3 (IRF3) and attenuates type I interferon responses. Notably, inhibition of SCoV2-PLpro with GRL-0617 impairs the virus-induced cytopathogenic effect, maintains the antiviral interferon pathway and reduces viral replication in infected cells. These results highlight a potential dual therapeutic strategy in which targeting of SCoV2-PLpro can suppress SARS-CoV-2 infection and promote antiviral immunity. Show less
Chakrabarti, M.; Al-Sammarraie, N.; Gebere, M.G.; Bhattacharya, A.; Chopra, S.; Johnson, J.; ... ; Azhar, M. 2020
Transforming growth factor beta3 (TGFB3) gene mutations in patients of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD1) and Loeys-Dietz syndrome-5 (LDS5)/Rienhoff syndrome are... Show moreTransforming growth factor beta3 (TGFB3) gene mutations in patients of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD1) and Loeys-Dietz syndrome-5 (LDS5)/Rienhoff syndrome are associated with cardiomyopathy, cardiac arrhythmia, cardiac fibrosis, cleft palate, aortic aneurysms, and valvular heart disease. Although the developing heart of embryos express Tgfb3, its overarching role remains unclear in cardiovascular development and disease. We used histological, immunohistochemical, and molecular analyses of Tgfb3(-/-) fetuses and compared them to wildtype littermate controls. The cardiovascular phenotypes were diverse with approximately two thirds of the Tgfb3(-/-) fetuses having one or more cardiovascular malformations, including abnormal ventricular myocardium (particularly of the right ventricle), outflow tract septal and alignment defects, abnormal aortic and pulmonary trunk walls, and thickening of semilunar and/or atrioventricular valves. Ventricular septal defects (VSD) including the perimembranous VSDs were observed in Tgfb3(-/-) fetuses with myocardial defects often accompanied by the muscular type VSD. In vitro studies using TGF beta 3-deficient fibroblasts in 3-D collagen lattice formation assays indicated that TGF beta 3 was required for collagen matrix reorganization. Biochemical studies indicated the 'paradoxically' increased activation of canonical (SMAD-dependent) and noncanonical (MAP kinase-dependent) pathways. TGF beta 3 is required for cardiovascular development to maintain a balance of canonical and noncanonical TGF beta signaling pathways. Show less
Chakrabarti, M.; Al-Sammarraie, N.; Gebere, M.G.; Bhattacharya, A.; Chopra, S.; Johnson, J.; ... ; Azhar, M. 2020
