STING nuclear partners contribute to innate immune signaling responses.

STimulator of INterferon Genes (STING) is an adaptor for cytoplasmic DNA sensing by cGAMP/cGAS that helps trigger innate immune responses (IIRs). Although STING is mostly localized in the ER, we find a separate inner nuclear membrane pool of STING that increases mobility and redistributes to the outer nuclear membrane upon IIR stimulation by transfected dsDNA or dsRNA mimic poly(I:C). Immunoprecipitation of STING from isolated nuclear envelopes coupled with mass spectrometry revealed a distinct nuclear envelope-STING proteome consisting of known nuclear membrane proteins and enriched in DNA- and RNA-binding proteins. Seventeen of these nuclear envelope STING partners are known to bind direct interactors of IRF3/7 transcription factors, and testing a subset of these revealed STING partners SYNCRIP, MEN1, DDX5, snRNP70, RPS27a, and AATF as novel modulators of dsDNA-triggered IIRs. Moreover, we find that SYNCRIP is a novel antagonist of the RNA virus, influenza A, potentially shedding light on reports of STING inhibition of RNA viruses.

Ecotoxicological study of six drugs in Aliivibrio fischeri, Daphnia magna and Raphidocelis subcapitata.

The presence of drugs in the environment is an emerging issue in the scientific community. It has been shown that these substances are active chemicals that consequently affect aquatic organisms and, finally, humans as end users. To evaluate the toxicity of these compounds and how they affect the environment, it is important to perform systematic ecotoxicological and physicochemical studies. The best way to address this problem is to conduct studies on different aquatic trophic levels. In this work, an ecotoxicological study of six drugs (anhydrous caffeine, diphenhydramine hydrochloride, gentamicin sulphate, lidocaine hydrochloride, tobramycin sulphate and enalapril maleate) that used three aquatic biological models (Raphidocelis subcapitata, Aliivibrio fischeri and Daphnia magna) was performed. Additionally, the concentration of chlorophyll in the algae R. subcapitata was measured. Furthermore, EC50 values were analysed using the Passino and Smith classification (PSC) method, which categorized the compounds as toxic or relatively toxic. All of the studied drugs showed clear concentration-dependent toxic effects. The toxicity of the chemicals depended on the biological model studied, with Raphidocelis subcapitata being the most sensitive species and Aliivibrio fischeri being the least sensitive. The results indicate that the most toxic compound, for all the studied biological models, was diphenhydramine hydrochloride. Graphical abstract.

Host Vesicle Fusion Protein VAPB Contributes to the Nuclear Egress Stage of Herpes Simplex Virus Type-1 (HSV-1) Replication.

The primary envelopment/de-envelopment of Herpes viruses during nuclear exit is poorly understood. In Herpes simplex virus type-1 (HSV-1), proteins pUL31 and pUL34 are critical, while pUS3 and some others contribute; however, efficient membrane fusion may require additional host proteins. We postulated that vesicle fusion proteins present in the nuclear envelope might facilitate primary envelopment and/or de-envelopment fusion with the outer nuclear membrane. Indeed, a subpopulation of vesicle-associated membrane protein-associated protein B (VAPB), a known vesicle trafficking protein, was present in the nuclear membrane co-locating with pUL34. VAPB knockdown significantly reduced both cell-associated and supernatant virus titers. Moreover, VAPB depletion reduced cytoplasmic accumulation of virus particles and increased levels of nuclear encapsidated viral DNA. These results suggest that VAPB is an important player in the exit of primary enveloped HSV-1 virions from the nucleus. Importantly, VAPB knockdown did not alter pUL34, calnexin or GM-130 localization during infection, arguing against an indirect effect of VAPB on cellular vesicles and trafficking. Immunogold-labelling electron microscopy confirmed VAPB presence in nuclear membranes and moreover associated with primary enveloped HSV-1 particles. These data suggest that VAPB could be a cellular component of a complex that facilitates UL31/UL34/US3-mediated HSV-1 nuclear egress.

NET23/STING promotes chromatin compaction from the nuclear envelope.

Changes in the peripheral distribution and amount of condensed chromatin are observed in a number of diseases linked to mutations in the lamin A protein of the nuclear envelope. We postulated that lamin A interactions with nuclear envelope transmembrane proteins (NETs) that affect chromatin structure might be altered in these diseases and so screened thirty-one NETs for those that promote chromatin compaction as determined by an increase in the number of chromatin clusters of high pixel intensity. One of these, NET23 (also called STING, MITA, MPYS, ERIS, Tmem173), strongly promoted chromatin compaction. A correlation between chromatin compaction and endogenous levels of NET23/STING was observed for a number of human cell lines, suggesting that NET23/STING may contribute generally to chromatin condensation. NET23/STING has separately been found to be involved in innate immune response signaling. Upon infection cells make a choice to either apoptose or to alter chromatin architecture to support focused expression of interferon genes and other response factors. We postulate that the chromatin compaction induced by NET23/STING may contribute to this choice because the cells expressing NET23/STING eventually apoptose, but the chromatin compaction effect is separate from this as the condensation was still observed when cells were treated with Z-VAD to block apoptosis. NET23/STING-induced compacted chromatin revealed changes in epigenetic marks including changes in histone methylation and acetylation. This indicates a previously uncharacterized nuclear role for NET23/STING potentially in both innate immune signaling and general chromatin architecture.

Safety and feasibility of catheter ablation for atrioventricular nodal re-entrant tachycardia without fluoroscopic guidance.

BACKGROUND: Nonfluoroscopic intracardiac navigation systems reduce the dose of radiation in most ablation procedures. However, they have not been sufficiently studied as a sole guidance tool for electrode catheter handling. OBJECTIVE: The purpose of our study was to assess the feasibility and safety of catheter ablation for atrioventricular nodal re-entrant tachycardia (AVNRT) without the use of fluoroscopy. METHODS: We prospectively enrolled all of the patients with AVNRT (Group A) treated by catheter ablation guided only by a nonfluoroscopic intracardiac navigation system. These patients were compared with a matched control group of patients (Group B) who had undergone an ablation procedure for AVNRT guided only by fluoroscopy in the preceding months. We compared the success rate and the rate of complications and recurrences. We also compared the procedure and radiofrequency times. RESULTS: Fifty patients were enrolled in each group. The procedure was successful in 100% in Group A versus 96% in Group B (P = .15). One patient in Group A and 4 patients in Group B suffered nonserious complications (P = NS). The mean fluoroscopy time in Group B was 18 +/- 16 min (range 3.5 to 77, total 924). In 1 case in Group A (2%), the use of fluoroscopy was required. Procedure and radiofrequency times did not differ between the 2 groups. A recurrence developed in 2 patients in each group (P = NS). CONCLUSIONS: Catheter ablation for AVNRT without fluoroscopic guidance is feasible and safe, and does not prolong procedure time. The reduction in radiation dose is considerable for patients and professionals.