ABSTRACT
BACKGROUND: The transmembrane protease serine 2 (TMPRSS2) proteolytically activates the envelope proteins of several viruses for viral entry via membrane fusion and is therefore an interesting and promising target for the development of broad-spectrum antivirals. However, the use of a host protein as a target may lead to potential side effects, especially on the immune system. We examined the effect of a genetic deletion of TMPRSS2 on dendritic cells. METHODS: Bone marrow cells from wild-type (WT) and TMPRSS2-deficient mice (TMPRSS2-/-) were differentiated to plasmacytoid dendritic cells (pDCs) and classical DCs (cDCs) and activated with various toll-like receptor (TLR) agonists. We analyzed the released cytokines and the mRNA expression of chemokine receptors, TLR7, TLR9, IRF7 and TCF4 stimulation. RESULTS: In cDCs, the lack of TMPRSS2 led to an increase in IL12 and IFNγ in TLR7/8 agonist resiquimod or TLR 9 agonist ODN 1668-activated cells. Only IL-10 was reduced in TMPRSS2-/- cells in comparison to WT cells activated with ODN 1668. In resiquimod-activated pDCs, the lack of TMPRSS2 led to a decrease in IL-6, IL-10 and INFγ. ODN 1668 activation led to a reduction in IFNα. The effect on receptor expression in pDCs and cDCs was low. CONCLUSION: The effect of TMPRSS2 on pDCS and cDCs depends on the activated TLR, and TMPRSS2 seems to affect cytokine release differently in pDCs and cDCs. In cDCs, TMPRSS2 seems to suppress cytokine release, whereas in pDCS TMPRSS2 possibly mediates cytokine release.
ABSTRACT
Objective: COVID19 is associated with vascular inflammation. IFN-alpha (IFNa) and IFN-lambda3 (IFNl3) are potent cytokines produced in viral infections. Their effects involve interferon-stimulated genes (ISGs) and may influence expression of angiotensin-converting enzyme 2 (ACE2), the receptor for S-protein (S1P) of SARS-CoV-2. We hypothesized that S1P-induced immune/inflammatory responses in endothelial cells (EC) are mediated via IFN-activated pathways Design and methods: Human ECs were stimulated with S1P (1 mg/mL), IFNa (100ng/mL) or IFNl3 (100IU/mL). Because ACE2, ADAM17 and TMPRSS2 are important for SARS-CoV-2 infection, we used inhibitors of ADAM17 (marimastat, 3.8 nM), ACE2 (MLN4760, 440pM), and TMPRSS2 (camostat, 50 mM). Gene and protein expression was investigated by real-time PCR and immunoblotting, respectively. Vascular function was assessed in mesenteric arteries from wild-type (WT) normotensive and hypertensive (LinA3) mice and in ISG15-deficient (ISG15KO) mice. Results: S1P increased expression of IFNa (3-fold), IFNl3 (4-fold) and ISGs (2-fold) in EC (p < 0.05). EC responses to IFNa (ISG15: 16-fold) were greater than to IFNl3 (ISG15: 1.7-fold) (p < 0.05). S1P increased gene expression of IL-6 (1.3-fold), TNFa (6.2-fold) and IL-1b (3.3-fold), effects that were amplified by IFNs. Only the ADAM17 inhibitor marimastat inhibited S1P effects. IFNa and IFNl3 increase protein expression of ADAM17 (27%) and TMPRSS2 (38%). No changes were observed on ACE2 expression. This was associated with increased phosphorylation of Stat1 (134%), Stat2 (102%), ERK1/2 (42%). EC production of IL-6 was increased by IFNa (1,230pg/mL) and IFNl3 (1,124pg/mL) vs control (591pg/mL). Nitric oxide generation and eNOS phosphorylation (Ser1177) were reduced by IFNa (40%) and IFNl3 (40%). Vascular functional responses demonstrated that endothelium-dependent vasorelaxation (% Emax) in vessels from WT-mice stimulated with IFNa (67%) and IFNl3 (71%) were reduced vs control (82%) (p < 0.05). Responses were not altered in vessels from ISG15KO mice. Increased contraction was observed only in vessels from hypertensive mice treated with IFNa (9.1 ± 0.5mN vs control: 7.3 ± 0.3mN) (p < 0.05). Conclusions: In ECs, S1P, IFNa and IFNl3 increased ISG15 and IL-6 by mechanisms dependent on ADAM17. IFNs amplifies endothelial cell inflammatory responses and induced vascular dysfunction through ISG15-dependent mechanisms, with augmented effects in hypertension. Our findings demonstrate that S1P induces immune/inflammatory responses that may be important in endotheliitis associated with COVID-19. This may be especially important in the presence of cardiovascular risk factors, including hypertension.
ABSTRACT
Background: There is a growing interest in airway inflammation and mental health. Recent genetic and epidemiological evidence supports an association between PTSD and asthma however, contributory immune mediators/mechanisms are unclear. Recent work from our group employs mouse aeroallergen, house dust mite (HDM) models to examine the role of severe asthma linked inflammatory T helper cells, Th17 and interleukin 17 (IL-17A) in regulating PTSD-relevant behaviors. Methods: A combination of behavioral, immunological, transgenic and transcriptomic approaches were used. 1) BALBc-C5a receptor treatment that shifts Th2 mild asthma phenotype to Th17/IL17a expansion and robust airway inflammation;2) IL-17a receptor knockout mice and 3) RNAseq transcriptomics of cortical and blood brain barrier compromised area, subfornical organ (SFO) tissue was performed. Fear conditioning and extinction was assessed as a PTSD-relevant behavior. Results: Induction of Th17/IL-17 in the BALBc/anti-C5aR1 treated mice resulted in compromised fear extinction and increased fear reinstatement. Absence of IL-17 signaling in IL17Ra deficient mice attenuated HDM effects on fear extinction. Preliminary evidence suggests a potential of the SFO in translating HDM effects to the medial prefrontal cortex, an area regulating fear extinction. Transcriptomic analyses revealed modulation of immune T cell-targeted signaling pathways within the SFO in mice with Th17A expansion. Conclusion: Overall, our work provides novel insights on mechanisms by which mediators of severe airway inflammation, Th17/IL17A regulate fear memory of relevance to PTSD. Beyond asthma-PTSD, our findings have relevant implications for other pulmonary (e.g. COVID-19) and autoimmune inflammatory conditions and mental health.
ABSTRACT
Objective: COVID19-associated immunopathology is associated with increased production of interferon (IFN)-alpha (IFNα) and lambda3 (IFNL3). Effects of IFNs are mediated by interferon-stimulated genes (ISGs) and influence expression of angiotensin-converting enzyme 2 (ACE2), the receptor for S-protein (S1P) of SARS-CoV-2. Increasing evidence indicates vascular inflammation in cardiovascular sequelae of COVID19. We hypothesized that S1P-induced immune/inflammatory responses in endothelial cells (EC) are mediated via IFNα and IFNL3. Design and method: Human ECs were stimulated with S1P (1 μg/mL), IFNα (100ng/mL) or IFNL3 (100IU/mL). Because ACE2, metalloproteinase domain-17 (ADAM17) and type-II transmembrane serine protease (TMPRSS2) are important for SARS-CoV-2 infection, cells were treated with inhibitors of ADAM17 (marimastat, 3.8 nM), ACE2 (MLN4760, 440pM), and TMPRSS2 (camostat, 50 μM). Gene and protein expression was investigated by real-time PCR immunoblotting, respectively. Vascular function was assessed in mesenteric arteries from wild-type (WT) normotensive and hypertensive mice and in ISG15-deficient (ISG15KO) mice. Results: EC stimulated with S1P increased expression of IFNα (3-fold), IFNL3 (4-fold) and ISG (2-fold)(p < 0.05). EC exhibited higher responses to IFNα (ISG15: 16-fold) than to IFNL3 (ISG15: 1.7-fold)(p < 0.05). S1P increased gene expression of IL-6 (1.3-fold), TNFα (6.2-fold) and IL-1β (3.3-fold), effects that were maximized by IFNs. Only marimastat inhibited S1P effects. IL-6 was increased by IFNα (1,230pg/mL) and IFNL3 (1,124pg/mL) vs control (591pg/ mL). This was associated with increased phosphorylation of Stat1 (134%), Stat2 (102%), ERK1/2 (42%). Nitric oxide production and eNOS phosphorylation (Ser1177) were reduced by IFNα and (40%) and IFNL3 (40%). Reduced endothelium relaxation maximal response (%Emax) was observed in vessels from WTmice stimulated with IFNα (67%) and IFNL3 (71%) vs control (82%)(p < 0.05) but not in vessels from ISG15KO mice. Increased contraction was observed only in vessels from hypertensive mice treated with IFNα (9.1 ± 0.5mN vs control: 7.3 ± 0.3mN, p < 0.05). Conclusions: In ECs, S1P, IFNα and IFNL3 increased ISG15 and IL-6, processes that involve ADAM17. Inflammation induced by S1P was amplified by IFNs. IFNs induce vascular dysfunction through ISG15-dependent mechanisms, with augmented effects in hypertension. Our findings demonstrate that S1P induces immune/inflammatory responses that may be important in endotheliitis associated with COVID-19. This is especially important in the presence of cardiovascular risk factors, including hypertension.
ABSTRACT
Background: Strong genetic and epidemiological evidence supports an asthma-PTSD association, however, contributory immune mediators/mechanisms are unclear. Here, we examined a direct role of severe asthma associated Th17/ IL-17A in regulating PTSD-relevant behaviors using mouse aeroallergen house dust mite (HDM) models. Methods: 3 strategies were used: 1) BALBc-C5a receptor treatment that shifts Th2 mild asthma phenotype to Th17/IL17a expansion;2) IL-17a receptor knockout mice and 3) sufficiency testing with intracerebroventricular (ICV) administration of recombinant IL17a effects on behavior. Fear conditioning and extinction, maze exploration and social behaviors were assessed. Results: Absence of IL-17 signaling attenuated HDM effects on fear extinction while induction of Th17/IL-17 in the BALBc/anti-C5aR1 treated mice resulted in compromised fear extinction. ICV IL-17a promoted an anxiogenic phenotype and impaired social behaviors. Preliminary evidence suggests a role of cortical mechanisms (under investigation). Conclusion: Overall, our work highlights severe asthma inflammatory mediator IL17a in regulating PTSD-relevant behaviors. Beyond asthma-PTSD, our findings have relevant implications for other pulmonary (e.g. COVID-19) and autoimmune inflammatory conditions and PTSD risk.