Treatment of Experimental Candida Sepsis with a Janus Kinase Inhibitor Controls Inflammation and Prolongs Survival

Inhibition of the JAK/STAT Pathway With Baricitinib Reduces the Multiple Organ Dysfunction Caused by Hemorrhagic Shock in Rats

OBJECTIVE

The aim of this study was to investigate (a) the effects of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway inhibitor (baricitinib) on the multiple organ dysfunction syndrome (MODS) in a rat model of hemorrhagic shock (HS) and (b) whether treatment with baricitinib attenuates the activation of JAK/STAT, NF-κB, and NLRP3 caused by HS.

BACKGROUND

Posttraumatic MODS, which is in part due to excessive systemic inflammation, is associated with high morbidity and mortality. The JAK/STAT pathway is a regulator of numerous growth factor and cytokine receptors and, hence, is considered a potential master regulator of many inflammatory signaling processes. However, its role in trauma-hemorrhage is unknown.

METHODS

An acute HS rat model was performed to determine the effect of baricitinib on MODS. The activation of JAK/STAT, NF-κB, and NLRP3 pathways were analyzed by western blotting in the kidney and liver.

RESULTS

We demonstrate here for the first time that treatment with baricitinib (during resuscitation following severe hemorrhage) attenuates the organ injury and dysfunction and the activation of JAK/STAT, NF-κB, and NLRP3 pathways caused by HS in the rat.

CONCLUSIONS

Our results point to a role of the JAK/STAT pathway in the pathophysiology of the organ injury and dysfunction caused by trauma/hemorrhage and indicate that JAK inhibitors, such as baricitinib, may be repurposed for the treatment of the MODS after trauma and/or hemorrhage.

IL-23 signaling prevents ferroptosis-driven renal immunopathology during candidiasis

During infection the host relies on pattern-recognition receptors to sense invading fungal pathogens to launch immune defense mechanisms. While fungal recognition and immune effector responses are organ and cell type specific, during disseminated candidiasis myeloid cells exacerbate collateral tissue damage. The β-glucan receptor ephrin type-A 2 receptor (EphA2) is required to initiate mucosal inflammatory responses during oral Candida infection. Here we report that EphA2 promotes renal immunopathology during disseminated candidiasis. EphA2 deficiency leads to reduced renal inflammation and injury. Comprehensive analyses reveal that EphA2 restrains IL-23 secretion from and migration of dendritic cells. IL-23 signaling prevents ferroptotic host cell death during infection to limit inflammation and immunopathology. Further, host cell ferroptosis limits antifungal effector functions via releasing the lipid peroxidation product 4-hydroxynonenal to induce various forms of cell death. Thus, we identify ferroptotic cell death as a critical pathway of Candida-mediated renal immunopathology that opens a new avenue to tackle Candida infection and inflammation.

Ruxolitinib ameliorates progressive anemia and improves survival during episodes of emergency granulopoiesis in Fanconi C−/− mice

Fanconi anemia (FA) is an inherited disorder of DNA repair with hematologic manifestations that range from anemia to bone marrow failure to acute myeloid leukemia. In a murine model of FA (Fancc^-/- mice), we found bone marrow failure was accelerated by repeated attempts to induce emergency (stress) granulopoiesis, the process for granulocyte production during the innate immune response. Fancc^-/- mice exhibited an impaired granulocytosis response and died with profound anemia during repeated challenge. In the current study, we found erythropoiesis and serum erythropoietin decreased in Fancc^-/- and wild-type (Wt) mice as emergency granulopoiesis peaked. Serum erythropoietin returned to baseline during steady-state resumption, and compensatory proliferation of erythroid progenitors was associated with DNA damage and apoptosis in Fancc^-/- mice, but not Wt mice. The erythropoietin receptor activates Janus kinase 2 (Jak2), and we found treatment of Fancc^-/- mice with ruxolitinib (Jak1/2-inhibitor) decreased anemia, enhanced granulocytosis, delayed clonal progression and prolonged survival during repeated emergency granulopoiesis episodes. This was associated with a decrease in DNA damage and apoptosis in Fancc^-/- erythroid progenitors during this process. Transcriptome analysis of these cells identified enhanced activity of pathways for metabolism of reactive oxygen species, and decreased apoptosis- and autophagy-related pathways, as major ruxolitinib-effects in Fancc^-/- mice. In contrast, ruxolitinib influenced primarily pathways involved in proliferation and differentiation in Wt mice. Ruxolitinib is approved for treatment of myeloproliferative disorders and graft-versus-host disease, suggesting the possibility of translational use as a bone marrow protectant in FA.

Detecting Critical Functional Ingredients Group and Mechanism of Xuebijing Injection in Treating Sepsis

Sepsis is a systemic inflammatory reaction caused by various infectious or noninfectious factors, which can lead to shock, multiple organ dysfunction syndrome, and death. It is one of the common complications and a main cause of death in critically ill patients. At present, the treatments of sepsis are mainly focused on the controlling of inflammatory response and reduction of various organ function damage, including anti-infection, hormones, mechanical ventilation, nutritional support, and traditional Chinese medicine (TCM). Among them, Xuebijing injection (XBJI) is an important derivative of TCM, which is widely used in clinical research. However, the molecular mechanism of XBJI on sepsis is still not clear. The mechanism of treatment of "bacteria, poison and inflammation" and the effects of multi-ingredient, multi-target, and multi-pathway have still not been clarified. For solving this issue, we designed a new systems pharmacology strategy which combines target genes of XBJI and the pathogenetic genes of sepsis to construct functional response space (FRS). The key response proteins in the FRS were determined by using a novel node importance calculation method and were condensed by a dynamic programming strategy to conduct the critical functional ingredients group (CFIG). The results showed that enriched pathways of key response proteins selected from FRS could cover 95.83% of the enriched pathways of reference targets, which were defined as the intersections of ingredient targets and pathogenetic genes. The targets of the optimized CFIG with 60 ingredients could be enriched into 182 pathways which covered 81.58% of 152 pathways of 1,606 pathogenetic genes. The prediction of CFIG targets showed that the CFIG of XBJI could affect sepsis synergistically through genes such as TAK1, TNF-α, IL-1β, and MEK1 in the pathways of MAPK, NF-κB, PI3K-AKT, Toll-like receptor, and tumor necrosis factor signaling. Finally, the effects of apigenin, baicalein, and luteolin were evaluated by in vitro experiments and were proved to be effective in reducing the production of intracellular reactive oxygen species in lipopolysaccharide-stimulated RAW264.7 cells, significantly. These results indicate that the novel integrative model can promote reliability and accuracy on depicting the CFIGs in XBJI and figure out a methodological coordinate for simplicity, mechanism analysis, and secondary development of formulas in TCM.

Interleukin-6 Blocking vs. JAK-STAT Inhibition for Prevention of Lung Injury in Patients with COVID-19

The severe respiratory insufficiency observed during COVID-19 infection may not be directly related to a cytopathogenic effect induced by the virus itself, but to an exaggerated and inappropriate immune response. In an effort to reduce the severity of organ dysfunction, including respiratory insufficiency, monoclonal antibodies (Mabs) that block the interleukin-6 receptor, such as tocilizumab, sarilumab, and siltuximab, are under investigation for the treatment of COVID-19. However, blocking of just one of the many cytokines involved in the inflammatory reaction may not slow down the magnitude of the process. Since timing is important, the immune deficiency induced by IL6 blockade at the late immunodeficiency phase of sepsis that follows the initial inflammatory response may be detrimental. Finally, monitoring the degree and duration of IL6 blockade may be challenging because of the long half-life of Mabs (2-3 weeks). Pro- and anti-inflammatory cytokines act through a common JAK-STAT signaling pathway, which can be inhibited by JAK-STAT inhibitors. Ruxolitinib, a tyrosine kinase inhibitor selective for JAK1, 2, blocks many pro- and anti-inflammatory cytokines including IL6. Ruxolitinib has favorable pharmacodynamics and an acceptable safety profile. The short half-life (4-6 h) of the drug offers the opportunity for ideal monitoring of the degree and duration of cytokine blocking, simply by the adjusting dose and duration of therapy. From a theoretical point of view, the balanced control of cytokine blockade throughout the course of the septic process should be the cornerstone of modern management. According to this hypothesis, maximization of blocking should be attempted at the phase of hyper-inflammation for preventing severe organ damage, while pro-inflammatory blockade should be minimized at the late phase of immunoparalysis for prevention of secondary infections. Based on the above considerations, we consider that the efficacy and safety of this drug deserves testing in the context of a controlled randomized trial.

JAK-STAT Targeting Offers Novel Therapeutic Opportunities in Sepsis

Sepsis is a life-threatening condition caused by exaggerated host responses to infections taking place in two phases: (i) a systemic (hyper)inflammatory response syndrome (SIRS), participating in multiple organ failure (MOF), a major complication of septic shock, followed by (ii) a compensatory anti-inflammatory response syndrome (CARS), leading to sepsis-induced immunosuppression and resulting in late infections and long-term mortality. The Janus kinase-signal transducer and activator of transcription (JAK-STAT)-dependent signaling pathway is involved in both manifestations, hence playing a key role during sepsis. It is also involved in emergency myelopoiesis, which participates in host defense. The aim of this review is to highlight and refine the recent implications of this signaling pathway in sepsis and illustrate why its central position makes it a potential biomarker and therapeutic target.

"Small" Intestinal Immunopathology Plays a "Big" Role in Lethal Cytokine Release Syndrome, and Its Modulation by Interferon-γ, IL-17A, and a Janus Kinase Inhibitor

Chimeric antigen receptor T cell (CART) therapy, administration of certain T cell-agonistic antibodies, immune check point inhibitors, coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome–coronavirus 2 (SARS-CoV-2) and Toxic shock syndrome (TSS) caused by streptococcal as well as staphylococcal superantigens share one common complication, that is T cell-driven cytokine release syndrome (CRS) accompanied by multiple organ dysfunction (MOD). It is not understood whether the failure of a particular organ contributes more significantly to the severity of CRS. Also not known is whether a specific cytokine or signaling pathway plays a more pathogenic role in precipitating MOD compared to others. As a result, there is no specific treatment available to date for CRS, and it is managed only symptomatically to support the deteriorating organ functions and maintain the blood pressure. Therefore, we used the superantigen-induced CRS model in HLA-DR3 transgenic mice, that closely mimics human CRS, to delineate the immunopathogenesis of CRS as well as to validate a novel treatment for CRS. Using this model, we demonstrate that (i) CRS is characterized by a rapid rise in systemic levels of several Th1/Th2/Th17/Th22 type cytokines within a few hours, followed by a quick decline. (ii) Even though multiple organs are affected, small intestinal immunopathology is the major contributor to mortality in CRS. (iii) IFN-γ deficiency significantly protected from lethal CRS by attenuating small bowel pathology, whereas IL-17A deficiency significantly increased mortality by augmenting small bowel pathology. (iv) RNA sequencing of small intestinal tissues indicated that IFN-γ-STAT1-driven inflammatory pathways combined with enhanced expression of pro-apoptotic molecules as well as extracellular matrix degradation contributed to small bowel pathology in CRS. These pathways were further enhanced by IL-17A deficiency and significantly down-regulated in mice lacking IFN-γ. (v) Ruxolitinib, a selective JAK-1/2 inhibitor, attenuated SAg-induced T cell activation, cytokine production, and small bowel pathology, thereby completely protecting from lethal CRS in both WT and IL-17A deficient HLA-DR3 mice. Overall, IFN-γ-JAK-STAT-driven pathways contribute to lethal small intestinal immunopathology in T cell-driven CRS.

Insights into the role of the JAK/STAT signaling pathway in graft-versus-host disease

Allogeneic hematopoietic transplantation (allo-HCT) is a curative therapy for a variety of hematologic malignancies, primarily through immune-mediated clearance of malignant cells. This graft-versus-leukemia (GvL) effect is mediated by alloreactive donor T-cells against recipient malignant cells. Unfortunately, graft versus host disease is a potentially lethal complication of this procedure, also mediated by alloreactive donor T-cells against recipient normal tissues. Graft-versus-host disease (GVHD) remains a key contributor to nonrelapse mortality and long-term morbidity in patients undergoing allo-HCT. Reducing GVHD without interfering with - or ideally while enhancing - GvL, would improve outcomes and increase patient eligibility for allo-HCT. The JAK/STAT signaling pathway acts downstream of over 50 cytokines and is central to a wide variety of inflammatory pathways. These pathways play a role in the development and maintenance of GVHD throughout the disease process and within T-cells, B-cells, macrophages, neutrophils, and natural killer cells. Agents targeting JAK/STAT signaling pathways have shown clinical efficacy and gained US Food and Drug Administration approval for numerous diseases. Here, we review the preclinical and clinical evidence for the role of JAK/STAT signaling in the development and maintenance of GVHD and the utility of blocking agents at preventing and treating GVHD.

Repression of interferon β-regulated cytokines by the JAK1/2 inhibitor ruxolitinib in inflammatory human macrophages

Ruxolitinib is a Janus kinase (JAK) 1/2 inhibitor, currently used in the treatment of myeloproliferative neoplasms. It exerts potent anti-inflammatory activity, but the involved molecular and cellular mechanisms remain poorly understood. In order to gain insights about this point, ruxolitinib effects towards expression of main inflammatory cytokines were studied in human macrophages, which constitute a key-cell type implicated in inflammation. Analysis of mRNA expression of cytokines (n=84) by PCR array indicated that, among those induced by the pro-inflammatory stimulus lipopolysaccharide (LPS) (n=44), 61.4% (n=27) were repressed by 5μM ruxolitinib. The major inflammatory cytokines, interleukin (IL) 6 and tumor necrosis factor α, were notably down-regulated by ruxolitinib at both the mRNA and protein level. Other repressed cytokines included IL27 and the chemokines CCL2, CXCL9, CXCL10 and CXCL11, but not IL1β. The interferon (IFN) β/JAK/signal transducer and activator of transcription (STAT) pathway, well-activated by LPS in human macrophages as demonstrated by increased secretion of IFNβ, STAT1 phosphorylation, and up-regulation of reference IFNβ-responsive genes, was concomitantly blocked by the JAK inhibitor. Most of cytokines targeted by ruxolitinib were shown to be regulated by IFNβ in a JAK-sensitive manner. In addition, counteracting the IFNβ/JAK/STAT cascade using a blocking monoclonal antibody directed against IFNβ receptor resulted in a similar profile of cytokine repression to that observed in response to the JAK inhibitor. Overall, these data provide evidence for ruxolitinib-mediated repression of inflammatory cytokines in human macrophages through inhibition of the LPS/IFNβ/JAK/STAT signalling pathway, which probably contributes to the anti-inflammatory effects of the JAK inhibitor.

Risks of Ruxolitinib in STAT1 Gain-of-Function-Associated Severe Fungal Disease

Heterozygous STAT1 gain-of-function (GOF) mutations are associated with chronic mucocutaneous candidiasis and a broad spectrum of infectious, inflammatory, and vascular manifestations. We describe therapeutic failures with the Janus Kinase (JAK) inhibitor ruxolitinib in 2 STAT1 GOF patients with severe invasive or cutaneous fungal infections.

A study on the risk of fungal infection with tofacitinib (CP-690550), a novel oral agent for rheumatoid arthritis

Tofacitinib (CP-690550), an oral Janus kinase inhibitor, has shown significant efficacy in the treatment of rheumatoid arthritis through blocking the signaling pathways of pro-inflammatory cytokines. However, recent evidence suggests that long-term tofacitinib treatment is associated with increased risk of infection (e.g. tuberculosis) in patients. In the present study, we illustrate that tofacitinib administration significantly reduced the survival rate of mice given lethal or sub-lethal dose challenge with Candida albicans. This was related to the ability of tofacitinib to reverse TNFα- and IFNγ-enhanced candidacidal activity of murine polymorph nuclear cells (PMNs) and also to suppress chemokine CXCL5 expression and PMN infiltration in the infected tissues of mice. More importantly, tofacitinib significantly antagonized the ability of TNFα, IFNγ and GM-CSF to boost human PMNs in phagocytosis and direct killing of C. albicans in vitro. It also down-regulated reactive oxygen production and neutrophil extracellular trap formation by human PMNs stimulated with yeast-derived β-glucans in the presence of TNFα, IFNγ or GM-CSF. Our data emphasizes a significantly increased risk for opportunistic fungal infection associated long-term tofacitinib treatment in humans, likely through antagonizing the PMN-boosting effect of pro-inflammatory cytokines.

Balanced control of both hyper and hypo-inflammatory phases as a new treatment paradigm in sepsis

The immune response of the host against invading pathogens is clinically manifested as sepsis. Sepsis is a complicated process characterized by distinct phases that usually occur in a sequential manner. The initial hyper-inflammation helps in elimination of the pathogen, but potentially may lead to excessive tissue injury. Hypo-inflammation helps in restoring immune homeostasis, but may lead to significant immune suppression and death from secondary infections if not appropriately controlled. Immune-modulating intervention in sepsis should be based on a balanced control of both the hyper and the hypo-inflammatory phase.