PIAS3 suppresses acute graft-versus-host disease by modulating effector T and B cell subsets through inhibition of STAT3 activation

PIAS3 acts as a zinc sensor under zinc deficiency and plays an important role in myocardial ischemia/reperfusion injury

Alterations in zinc transporter expression in response to zinc loss protect cardiac cells from ischemia/reperfusion (I/R) injury. However, the underlying molecular mechanisms how cardiac cells sense zinc loss remains unclear. Here, we found that zinc deficiency induced ubiquitination and degradation of the protein inhibitor of activated STAT3 (PIAS3), which can alleviate myocardial I/R injury by activating STAT3 to promote the expression of ZIP family zinc transporter genes. The RING finger domain within PIAS3 is vital for PIAS3 degradation, as PIAS3-dRing (missing the RING domain) and PIAS3-Mut (zinc-binding site mutation) were resistant to degradation in the setting of zinc deficiency. Meanwhile, the RING finger domain within PIAS3 is critical for the inhibition of STAT3 activation. Moreover, PIAS3 knockdown increased cardiac Zn2+ levels and reduced myocardial infarction in mouse hearts subjected to I/R, whereas wild-type PIAS3 overexpression, but not PIAS3-Mut, reduced cardiac Zn2+ levels, and exacerbated myocardial infarction. These findings elucidate a unique mechanism of zinc sensing, showing that fast degradation of the zinc-binding regulatory protein PIAS3 during zinc deficiency can correct zinc dyshomeostasis and alleviate reperfusion injury.

Protein inhibitor of activated STAT3 (PIAS3) attenuates psoriasis and associated inflammation

Psoriasis is a common chronic inflammatory multisystem disease accompanied by hyperproliferation and inflammation of epidermal keratinocytes. Signal transducer and activator of transcription 3 (STAT3) is constitutively activated and plays an important role in epidermal keratinocytes of human psoriatic skin lesions. In this study, we investigated the effects of an endogenous STAT3 inhibitor, a protein inhibitor of activated STAT3 (PIAS3), on the proliferation and inflammation of psoriatic cells. The expression of PIAS3 in psoriatic tissues and healthy skin was analyzed using the Gene Expression Omnibus database and clinical samples. The human immortalized epidermal (HaCaT) cells were used to establish an in vitro psoriasis-like cell model. 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-thethrazolium (MTS) assay was used to detect cell proliferation. Flow cytometry was used to determine apoptosis levels. Real-time PCR, western blotting, and enzyme-linked immunosorbent assay (ELISA) were used to detect the expression levels of related factors. Furthermore, a mouse model of imiquimod (IMQ)-induced psoriatic dermatitis was established to verify the in vitro experimental results. The results showed that the mRNA and protein expression levels of PIAS3 were lower in psoriatic lesions than in normal tissues. PIAS3 inhibited the proliferation and promoted apoptosis of M5-induced HaCaT cells. Simultaneously, the mRNA and protein expression levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-8 (IL-8), and keratin 17 (K17) were significantly decreased and that of p53 was increased, thereby inhibiting the inflammatory response and promoting apoptosis. PIAS3 inhibited the transcription activity of STAT3 and noncanonical nuclear factor-kappaB (NF-κB). Furthermore, PIAS3 attenuated IMQ-induced psoriasis-like inflammation in mice. Our findings suggest that PIAS3 plays an important role in psoriasis by regulating the STAT3/NF-κB signaling pathway and p53. The lack of PIAS3 may represent a novel mechanism underlying the pathogenesis of psoriasis.

Dissecting the regulatory network of transcription factors in T cell phenotype/functioning during GVHD and GVT

Transcription factors play a major role in regulation and orchestration of immune responses. The immunological context of the response can alter the regulatory networks required for proper functioning. While these networks have been well-studied in canonical immune contexts like infection, the transcription factor landscape during alloactivation remains unclear. This review addresses how transcription factors contribute to the functioning of mature alloactivated T cells. This review will also examine how these factors form a regulatory network to control alloresponses, with a focus specifically on those factors expressed by and controlling activity of T cells of the various subsets involved in graft-versus-host disease (GVHD) and graft-versus-tumor (GVT) responses.

STAT signaling in the intestine

The Janus kinase (JAK), signal transducer of activation (STAT) pathway, discovered by investigating interferon gene induction, is now recognized as an evolutionary conserved signaling pathway employed by diverse cytokines, interferons, growth factors, and related molecules. Since its discovery, this pathway has become a paradigm for membrane-to-nucleus signaling and explains how a broad range of soluble factors such as cytokines and hormones, mediate their diverse functions. The understanding of JAK-STAT signaling in the intestine has not only impacted basic science research, particularly in the understanding of intercellular communication and cell-extrinsic control of gene expression, but it has also become a prototype for transition of bench to bedside research, culminating in the clinical implementation of pathway-specific therapeutics.

Serum Protein Changes in Pediatric Sepsis Patients Identified With an Aptamer-Based Multiplexed Proteomic Approach

OBJECTIVES

Sepsis, a life-threatening organ dysfunction caused by a dysregulated host response to infection, is a leading cause of death and disability among children worldwide. Identifying sepsis in pediatric patients is difficult and can lead to treatment delay. Our objective was to assess the host proteomic response to infection utilizing an aptamer-based multiplexed proteomics approach to identify novel serum protein changes that might help distinguish between pediatric sepsis and infection-negative systemic inflammation and hence can potentially improve sensitivity and specificity of the diagnosis of sepsis over current clinical criteria approaches.

DESIGN

Retrospective, observational cohort study.

SETTING

PICU and cardiac ICU, Seattle Children's Hospital, Seattle, WA.

PATIENTS

A cohort of 40 children with clinically overt sepsis and 30 children immediately postcardiopulmonary bypass surgery (infection-negative systemic inflammation control subjects) was recruited. Children with sepsis had a confirmed or suspected infection, two or more systemic inflammatory response syndrome criteria, and at least cardiovascular and/or pulmonary organ dysfunction.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Serum samples from 35 of the sepsis and 28 of the bypass surgery subjects were available for screening with an aptamer-based proteomic platform that measures 1,305 proteins to search for large-scale serum protein expression pattern changes in sepsis. A total of 111 proteins were significantly differentially expressed between the sepsis and control groups, using the linear models for microarray data (linear modeling) and Boruta (decision trees) R packages, with 55 being previously identified in sepsis patients. Weighted gene correlation network analysis helped identify 76 proteins that correlated highly with clinical sepsis traits, 27 of which had not been previously reported in sepsis.

CONCLUSIONS

The serum protein changes identified with the aptamer-based multiplexed proteomics approach used in this study can be useful to distinguish between sepsis and noninfectious systemic inflammation.

Protein inhibitor of activated STAT3 reduces peripheral arthritis and gut inflammation and regulates the Th17/Treg cell imbalance via STAT3 signaling in a mouse model of spondyloarthritis

Background

Spondyloarthritis (SpA) is chronic inflammatory arthritis, and interleukin (IL)-17 is crucial in SpA pathogenesis. Type 17 helper T (Th17) cells are one of major IL-17-secreting cells. Signal transducer and activator of transcription (STAT)-3 signaling induces Th17 differentiation. This study investigated the effects of protein inhibitor of activated STAT3 (PIAS3) on SpA pathogenesis. Curdlan was injected into SKG ZAP-70^W163C mice for SpA induction.

Methods

The PIAS3 or Mock vector was inserted into mice for 10 weeks. Clinical and histologic scores of the paw, spine, and gut were evaluated. The expression of IL-17, tumor necrosis factor-α (TNF-α), STAT3, and bone morphogenic protein (BMP) was measured. Confocal microscopy and flow cytometry were used to assess Th cell differentiation.

Results

PIAS3 significantly diminished the histologic scores of the paw and gut. PIAS3-treated mice displayed decreased expression of IL-17, TNF-α, and STAT3 in the paw, spine, and gut. BMP-2/4 expression was lower in the spines of PIAS3-treated mice. Th cell differentiation was polarized toward the upregulation of regulatory T cells (Tregs) and the downregulation of Th17 in PIAS3-treated mice.

Conclusion

PIAS3 had beneficial effects in mice with SpA by reducing peripheral arthritis and gut inflammation. Pro-inflammatory cytokines and Th17/Treg differentiation were controlled by PIAS3. In addition, BMPs were decreased in the spines of PIAS3-treated mice. These findings suggest that PIAS3 could have therapeutic benefits in patients with SpA.

Advance in Targeted Immunotherapy for Graft-Versus-Host Disease

Graft-versus-host disease (GVHD) is a serious and deadly complication of patients, who undergo hematopoietic stem cell transplantation (HSCT). Despite prophylactic treatment with immunosuppressive agents, 20–80% of recipients develop acute GVHD after HSCT. And the incidence rates of chronic GVHD range from 6 to 80%. Standard therapeutic strategies are still lacking, although considerable advances have been gained in knowing of the predisposing factors, pathology, and diagnosis of GVHD. Targeting immune cells, such as regulatory T cells, as well as tolerogenic dendritic cells or mesenchymal stromal cells (MSCs) display considerable benefit in the relief of GVHD through the deletion of alloactivated T cells. Monoclonal antibodies targeting cytokines or signaling molecules have been demonstrated to be beneficial for the prevention of GVHD. However, these remain to be verified in clinical therapy. It is also important and necessary to consider adopting individualized treatment based on GVHD subtypes, pathological mechanisms involved and stages. In the future, it is hoped that the identification of novel therapeutic targets and systematic research strategies may yield novel safe and effective approaches in clinic to improve outcomes of GVHD further. In this article, we reviewed the current advances in targeted immunotherapy for the prevention of GVHD.

Therapeutic effects of STAT3 inhibition by nifuroxazide on murine acute graft graft-vs.-host disease: Old drug, new use

Graft-vs.-host disease (GvHD) is a major and lethal complication of allogeneic bone marrow transplantation (allo-BMT). Although great development has been made, the treatment progress of this disorder is slow. Research has illustrated that STAT3 was critical for T cell alloactivation in GvHD. In the present study, the authors hypothesized that nifuroxazide, as the STAT3 inhibitor, treatment may attenuate the development of acute GvHD (aGvHD). The results demonstrated that nifuroxazide suppressed the development of aGvHD and significantly delayed aGvHD-induced lethality. Mice receiving nifuroxazide had mostly normal-appearing skin with minimal focal ulceration, mild edema and congestion in the liver, and a less-pronounced villus injury and less inflammatory infiltrate in the small intestine. Treatment with nifuroxazide inhibited the activation of STAT3, resulting in the regulation of the CD4⁺ T cells and CD4⁺CD25⁺ T cells and reduction of interferon-γ and tumor necrosis factor-α levels. In conclusion, nifuroxazide may be efficacious for post-transplant of GvHD, providing a potent drug for use as a prophylactic or as a second-line therapy for aGvHD in clinical trials.

Interleukin-6 in Allogeneic Stem Cell Transplantation: Its Possible Importance for Immunoregulation and As a Therapeutic Target

Allogeneic stem cell transplantation is associated with a high risk of treatment-related mortality mainly caused by infections and graft-versus-host disease (GVHD). GVHD is characterized by severe immune dysregulation and impaired regeneration of different tissues, i.e., epithelial barriers and the liver. The balance between pro- and anti-inflammatory cytokine influences the risk of GVHD. Interleukin-6 (IL-6) is a cytokine that previously has been associated with pro-inflammatory effects. However, more recent evidence from various autoimmune diseases (e.g., inflammatory bowel disease, rheumatoid arthritis) has shown that the IL-6 activity is more complex with important effects also on tissue homeostasis, regeneration, and metabolism. This review summarizes the current understanding of how pro-inflammatory IL-6 effects exerted during the peritransplant period shapes T-cell polarization with enhancement of Th17 differentiation and suppression of regulatory T cells, and in addition we also review and discuss the results from trials exploring non-selective IL-6 inhibition in prophylaxis and treatment of GVHD. Emerging evidence suggests that the molecular strategy for targeting of IL-6-initiated intracellular signaling is important for the effect on GVHD. It will therefore be important to further characterize the role of IL-6 in the pathogenesis of GVHD to clarify whether combined IL-6 inhibition of both trans- (i.e., binding of the soluble IL-6/IL-6 receptor complex to cell surface gp130) and cis-signaling (i.e., IL-6 ligation of the IL-6 receptor/gp130 complex) or selective inhibition of trans-signaling should be tried in the prophylaxis and/or treatment of GVHD in allotransplant patients.

Combined nifuroxazide and SAT05f therapy reduces graft-versus-host disease after experimental allogeneic bone marrow transplantation

Acute graft-versus-host disease (aGvHD) is the major barrier to the broader use of allogenetic hematopoietic stem cells. However, currently these are no highly specific and efficient drugs. Monotherapy is not sufficient and more efficient and safe therapeutic regimen are urgent need. Studies demonstrated TLR9 and Stat3 signal pathways are critical for antigen-presenting cell maturation and T-cell activation, which are important mediators in aGvHD. Specific block these two critical signal pathways using their inhibitors SAT05f and nifuroxazide may be the novel strategies for aGvHD therapy. The results showed combined therapy significantly decreased the severity of aGvHD and prolonged the survival rate. Furthermore, after treatment, the activation of CD4⁺ effect T cells was reduced, whereas Treg cells was increased, and the cytokine release was inhibited. In conclusion, combined therapy of nifuroxazide with SAT05f may be potential for the prevention or treatment of aGvHD, providing theoretic and experimental basis.

Improvement of Sclerodermatous Graft-Versus-Host Disease in Mice by Niclosamide

Sclerodermatous graft-versus-host disease, a frequent complication of allogeneic hematopoietic stem cell graft, shares many features with systemic sclerosis, such as production of autoantibodies and fibrosis of skin and inner organs. Recent reports on the implication of signal transducer and activator of transcription 3 and of Wnt/β-catenin in fibrosis have prompted us to investigate the effects of the inhibition of both signaling pathways in a mouse model of sclerodermatous graft-versus-host disease, using niclosamide, an anthelmintic drug, with a well-defined safety profile. Sclerodermatous graft-versus-host disease was induced in BALB/c mice by B10.D2 bone marrow and spleen cell transplantation. Mice were treated every other day, 5 days a week, for 5 weeks by niclosamide. Clinical and biological features were studied 42 days after transplantation. Niclosamide reversed clinical symptoms including alopecia, vasculitis, and diarrhea and prevented fibrosis of the skin and visceral organs. Beneficial immunological effects were also observed: niclosamide decreased the production of effector memory CD4 and CD8 T cells, T-cell infiltration of the skin and visceral organs, and decreased productions of IL-4 and IL-13, and autoimmune B-cell activation. The improvement provided by niclosamide in the mouse model of sclerodermatous graft-versus-host disease provides a rationale for the evaluation of niclosamide in the management of patients affected by systemic fibrotic disease.

High expression of heme oxygenase-1 in target organs may attenuate acute graft-versus-host disease through regulation of immune balance of TH17/Treg

The high incidence of acute graft-versus-host disease (aGVHD) is a serious complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Grades III and IV aGVHD are the leading causes of death in allo-HSCT recipients. Heme oxygenase-1(HO-1) has anti-inflammatory and immune-regulatory functions. In this study, we evaluated the none GVHD and grade I-IV patients samples which were collected at the first re-examination after successful allo-HSCT, we found that expressions of HO-1 mRNA in the bone marrow and peripheral blood mononuclear cells of allo-HSCT recipients who had subsequent non-GVHD and grade I aGVHD were significantly higher than those in patients with Grade III-IV aGVHD. We then demonstrated that enhanced expression of HO-1 in target organs by infusing HO-1-gene-modified Mesenchymal stem cells (MSCs) alleviated the clinical and histopathological severity of aGVHD in experimental mice. Flow cytometry revealed a higher expression of Treg cells and a lower expression of TH17 cells in splenic and lymph node tissues of mice with enhanced HO-1 expression, as compared to that in the aGVHD mice. This was further substantiated by lower expression levels of ROR-Υt and IL-17A mRNA, and higher levels of Foxp3 mRNA in the splenic tissue of mice with enhanced HO-1 expression. Our results indicate that high expression of HO-1 may reduce the severity of aGVHD by regulation of the TH17/Treg balance.

Immune deficiency vs. immune excess in inflammatory bowel diseases-STAT3 as a rheo-STAT of intestinal homeostasis

Genome-wide association studies have provided many genetic alterations, conferring susceptibility to multifactorial polygenic diseases, such as inflammatory bowel diseases. Yet, how specific genetic alterations functionally affect intestinal inflammation often remains elusive. It is noteworthy that a large overlap of genes involved in immune deficiencies with those conferring inflammatory bowel disease risk has been noted. This has provided new arguments for the debate on whether inflammatory bowel disease arises from either an excess or a deficiency in the immune system. In this review, we highlight the functional effect of an inflammatory bowel disease-risk allele, which cannot be deduced from genome-wide association studies data alone. As exemplified by the transcription factor signal transducer and activator of transcription 3 (STAT3), we show that a single gene can have a plethora of effects in various cell types of the gut. These effects may individually contribute to the restoration of intestinal homeostasis on the one hand or pave the way for excessive immunopathology on the other, as an inflammatory "rheo-STAT".