Profiling Differential Effects of 5 Selective Serotonin Reuptake Inhibitors on TLRs-Dependent and -Independent IL-6 Production in Immune Cells Identifies Fluoxetine as Preferred Anti-Inflammatory Drug Candidate

The IRE1α-XBP1 arm of the unfolded protein response is a host factor activated in SARS-CoV-2 infection

SARS-CoV-2 infection can cause severe pneumonia, wherein exacerbated inflammation plays a major role. This is reminiscent of the process commonly termed cytokine storm, a condition dependent on a disproportionated production of cytokines. This state involves the activation of the innate immune response by viral patterns and coincides with the biosynthesis of the biomass required for viral replication, which may overwhelm the capacity of the endoplasmic reticulum and drive the unfolded protein response (UPR). The UPR is a signal transduction pathway composed of three branches that is initiated by a set of sensors: inositol-requiring protein 1 (IRE1), protein kinase RNA-like ER kinase (PERK), and activating transcription factor 6 (ATF6). These sensors control adaptive processes, including the transcriptional regulation of proinflammatory cytokines. Based on this background, the role of the UPR in SARS-CoV-2 replication and the ensuing inflammatory response was investigated using in vivo and in vitro models of infection. Mice and Syrian hamsters infected with SARS-CoV-2 showed a sole activation of the Ire1α-Xbp1 arm of the UPR associated with a robust production of proinflammatory cytokines. Human lung epithelial cells showed the dependence of viral replication on the expression of UPR-target proteins branching on the IRE1α-XBP1 arm and to a lower extent on the PERK route. Likewise, activation of the IRE1α-XBP1 branch by Spike (S) proteins from different variants of concern was a uniform finding. These results show that the IRE1α-XBP1 system enhances viral replication and cytokine expression and may represent a potential therapeutic target in SARS-CoV-2 severe pneumonia.

Immuno-oncological effects of standard anticancer agents and commonly used concomitant drugs: an in vitro assessment

BACKGROUND

It has become evident in the field of oncology that the outcome of medical treatment is influenced by the combined effect exerted on both cancer- and immune cells. Therefore, we evaluated potential immunological effects of 46 standard anticancer agents and 22 commonly administered concomitant non-cancer drugs.

METHODS

We utilized a miniaturized in vitro model system comprised of fluorescently labeled human colon and lung cancer cell lines grown as monocultures and co-cultured with activated peripheral blood mononuclear cells (PBMCs). The Bliss Independence Model was then applied to detect antagonism and synergy between the drugs and activated immune cells.

RESULTS

Among the standard anticancer agents, tyrosine kinase inhibitors (TKIs) stood out as the top inducers of both antagonism and synergy. Ruxolitinib and dasatinib emerged as the most notably antagonistic substances, exhibiting the lowest Bliss scores, whereas sorafenib was shown to synergize with activated PBMCs. Most concomitant drugs did not induce neither antagonism nor synergy. However, the statins mevastatin and simvastatin were uniquely shown to synergize with activated PBMC at all tested drug concentrations in the colon cancer model.

CONCLUSION

We utilized a miniaturized tumor-immune model to enable time and cost-effective evaluation of a broad panel of drugs in an immuno-oncology setting in vitro. Using this approach, immunomodulatory effects exerted by TKIs and statins were identified.

Sertraline modulates hippocampal plasticity and learning via sigma 1 receptors, cellular stress and neurosteroids

In addition to modulating serotonin transport, selective serotonin reuptake inhibitors (SSRIs) have multiple other effects that may contribute to clinical effects, and some of these latter actions prompt repurposing of SSRIs for non-psychiatric indications. We recently observed that the SSRIs fluvoxamine and fluoxetine prevent the acute adverse effects of pro-inflammatory stimulation on long-term potentiation (LTP) in the CA1 hippocampal region. Sertraline showed markedly different effects, acutely inhibiting LTP at a low micromolar concentration through inverse agonism of sigma 1 receptors (S1Rs). In the present studies, we pursued mechanisms contributing to sertraline modulation of LTP in rat hippocampal slices. We found that sertraline partially inhibits synaptic responses mediated by N-methyl-D-aspartate receptors (NMDARs) via effects on NMDARs that express GluN2B subunits. A selective S1R antagonist (NE-100), but not an S1R agonist (PRE-084) blocked effects on NMDARs, despite the fact that both S1R ligands were previously shown to prevent LTP inhibition. Both NE-100 and PRE-084, however, prevented adverse effects of sertraline on one-trial learning. Because of the important role that S1Rs play in modulating endoplasmic reticulum stress, we examined whether inhibitors of cellular stress alter effects of sertraline. We found that two stress inhibitors, ISRIB and quercetin, prevented LTP inhibition, as did inhibitors of the synthesis of endogenous neurosteroids, which are homeostatic regulators of cellular stress. These studies highlight complex effects of sertraline, S1Rs and neurosteroids on hippocampal function and have relevance for understanding therapeutic and adverse drug actions.

Fluvoxamine for the treatment of COVID-19

BACKGROUND

Fluvoxamine is a selective serotonin reuptake inhibitor (SSRI) that has been approved for the treatment of depression, obsessive-compulsive disorder, and a variety of anxiety disorders; it is available as an oral preparation. Fluvoxamine has not been approved for the treatment of infections, but has been used in the early treatment of people with mild to moderate COVID-19. As there are only a few effective therapies for people with COVID-19 in the community, a thorough understanding of the current evidence regarding the efficacy and safety of fluvoxamine as an anti-inflammatory and possible anti-viral treatment for COVID-19, based on randomised controlled trials (RCTs), is needed.

OBJECTIVES

To assess the efficacy and safety of fluvoxamine in addition to standard care, compared to standard care (alone or with placebo), or any other active pharmacological comparator with proven efficacy for the treatment of COVID-19 outpatients and inpatients.

SEARCH METHODS

We searched the Cochrane COVID-19 Study Register (including Cochrane Central Register of Controlled Trials, MEDLINE, Embase, ClinicalTrials.gov, WHO ICTRP, medRxiv), Web of Science and WHO COVID-19 Global literature on COVID-19 to identify completed and ongoing studies up to 1 February 2022.

SELECTION CRITERIA

We included RCTs that compared fluvoxamine in addition to standard care (also including no intervention), with standard care (alone or with placebo), or any other active pharmacological comparator with proven efficacy in clinical trials for the treatment of people with confirmed COVID-19, irrespective of disease severity, in both inpatients and outpatients. Co-interventions needed to be the same in both study arms. We excluded studies comparing fluvoxamine to other pharmacological interventions with unproven efficacy.

DATA COLLECTION AND ANALYSIS

We assessed risk of bias of primary outcomes using the Cochrane Risk of Bias 2 tool for RCTs. We used GRADE to rate the certainty of evidence to treat people with asymptomatic to severe COVID-19 for the primary outcomes including mortality, clinical deterioration, clinical improvement, quality of life, serious adverse events, adverse events of any grade, and suicide or suicide attempt.

MAIN RESULTS

We identified two completed studies with a total of 1649 symptomatic participants. One study was conducted in the USA (study with 152 participants, 80 and 72 participants per study arm) and the other study in Brazil (study with 1497 high-risk participants for progression to severe disease, 741 and 756 participants per study arm) among outpatients with mild COVID-19. Both studies were double-blind, placebo-controlled trials in which participants were prescribed 100 mg fluvoxamine two or three times daily for a maximum of 15 days. We identified five ongoing studies and two studies awaiting classification (due to translation issues, and due to missing published data). We found no published studies comparing fluvoxamine to other pharmacological interventions of proven efficacy. We assessed both included studies to have an overall high risk of bias. Fluvoxamine for the treatment of COVID-19 in inpatients We did not identify any completed studies of inpatients. Fluvoxamine for the treatment of COVID-19 in outpatients Fluvoxamine in addition to standard care may slightly reduce all-cause mortality at day 28 (RR 0.69, 95% CI 0.38 to 1.27; risk difference (RD) 9 per 1000; 2 studies, 1649 participants; low-certainty evidence), and may reduce clinical deterioration defined as all-cause hospital admission or death before hospital admission (RR 0.55, 95% CI 0.16 to 1.89; RD 57 per 1000; 2 studies, 1649 participants; low-certainty evidence). We are very uncertain regarding the effect of fluvoxamine on serious adverse events (RR 0.56, 95% CI 0.15 to 2.03; RD 54 per 1000; 2 studies, 1649 participants; very low-certainty evidence) or adverse events of any grade (RR 1.06, 95% CI 0.82 to 1.37; RD 7 per 1000; 2 studies, 1649 participants; very low-certainty evidence). Neither of the studies reported on symptom resolution (clinical improvement), quality of life or suicide/suicide attempt.

AUTHORS' CONCLUSIONS

Based on a low-certainty evidence, fluvoxamine may slightly reduce all-cause mortality at day 28, and may reduce the risk of admission to hospital or death in outpatients with mild COVID-19. However, we are very uncertain regarding the effect of fluvoxamine on serious adverse events, or any adverse events. In accordance with the living approach of this review, we will continually update our search and include eligible trials as they arise, to complete any gaps in the evidence.