Persistent STAT5 phosphorylation and epigenetic dysregulation of GM-CSF and PGS2/COX2 expression in Type 1 diabetic human monocytes

STATs, promising targets for the treatment of autoimmune and inflammatory diseases

Cytokines play a crucial role in the pathophysiology of autoimmune and inflammatory diseases, with over 50 cytokines undergoing signal transduction through the Signal Transducers and Activators of Transcription (STAT) signaling pathway. Recent studies have solidly confirmed the pivotal role of STATs in autoimmune and inflammatory diseases. Therefore, this review provides a detailed summary of the immunological functions of STATs, focusing on exploring their mechanisms in various autoimmune and inflammatory diseases. Additionally, with the rapid advancement of structural biology in the field of drug discovery, many STAT inhibitors have been identified using structure-based drug design strategies. In this review, we also examine the structures of STAT proteins and compile the latest research on STAT inhibitors currently being tested in animal models and clinical trials for the treatment of immunological diseases, which emphasizes the feasibility of STATs as promising therapeutic targets and provides insights into the design of the next generation of STAT inhibitors.

Mechanism of Action of Oral Salmonella-Based Vaccine to Prevent and Reverse Type 1 Diabetes in NOD Mice

A combination therapy of preproinsulin (PPI) and immunomodulators (TGFβ+IL10) orally delivered via genetically modified Salmonella and anti-CD3 promoted glucose balance in in NOD mice with recent onset diabetes. The Salmonella bacteria were modified to express the diabetes-associated antigen PPI controlled by a bacterial promoter in conjunction with over-expressed immunomodulating molecules. The possible mechanisms of action of this vaccine to limit autoimmune diabetes remained undefined. In mice, the vaccine prevented and reversed ongoing diabetes. The vaccine-mediated beneficial effects were associated with increased numbers of antigen-specific CD4+CD25+Foxp3+ Tregs, CD4+CD49b+LAG3+ Tr1-cells, and tolerogenic dendritic-cells (tol-DCs) in the spleens and lymphatic organs of treated mice. Despite this, the immune response to Salmonella infection was not altered. Furthermore, the vaccine effects were associated with a reduction in islet-infiltrating lymphocytes and an increase in the islet beta-cell mass. This was associated with increased serum levels of the tolerogenic cytokines (IL10, IL2, and IL13) and chemokine ligand 2 (CCL2) and decreased levels of inflammatory cytokines (IFNγ, GM-CSF, IL6, IL12, and TNFα) and chemokines (CXCL1, CXCL2, and CXCL5). Overall, the data suggest that the Salmonella-based vaccine modulates the immune response, reduces inflammation, and promotes tolerance specifically to an antigen involved in autoimmune diabetes.

PAK1 overexpression promotes myxofibrosarcoma angiogenesis through STAT5B-mediated CSF2 transactivation: clinical and therapeutic relevance of amplification and nuclear entry

Myxofibrosarcoma is genetically complex without established nonsurgical therapies. In public datasets, PAK1 was recurrently gained with mRNA upregulation. Using myxofibrosarcoma cells, we explored the oncogenic underpinning of PAK1 with genetic manipulation and a pan-PAK inhibitor (PF3758309). Myxofibrosarcoma specimens were analyzed for the levels of PAK1, phospho-PAKT423, CSF2 and microvascular density (MVD) and those of PAK1 gene and mRNA. PAK1-expressing xenografts were assessed for the effects of PF3758309 and CSF2 silencing. Besides pro-proliferative and pro-migrator/pro-invasive attributes, PAK1 strongly enhanced angiogenesis in vitro, which, not phenocopied by PAK2-4, was identified as CSF2-mediated using antibody arrays. PAK1 underwent phosphorylation at tyrosines153,201,285 and threonine423 to facilitate nuclear entry, whereby nuclear PAK1 bound STAT5B to co-transactivate the CSF2 promoter, increasing CSF2 secretion needed for angiogenesis. Angiogenesis driven by PAK1-upregulated CSF2 was negated by CSF2 silencing, anti-CSF2, and PF3758309. Clinically, overexpressed whole-cell phospho-PAKT423, related to PAK1 amplification, was associated with increased grades, stages, and PAK1 mRNA, higher MVD, and CSF2 overexpression. Overexpressed whole-cell phospho-PAKT423 and CSF2 independently portended shorter metastasis-free survival and disease-specific survival, respectively. In vivo, both CSF2 silencing and PF3758309 suppressed PAK1-driven tumor proliferation and angiogenesis. Conclusively, the nuclear entry of overexpressed/activated PAK1 endows myxofibrosarcomas with pro-angiogenic function, highlighting the vulnerable PAK1/STAT5B/CSF2 regulatory axis.

Naringenin as a natural immunomodulator against T cell-mediated autoimmune diseases: literature review and network-based pharmacology study

T cells, especially CD4+ T helper (Th) cells, play a vital role in the pathogenesis of specific autoimmune diseases. Naringenin, a citrus flavonoid, exhibits anti-inflammatory, anti-oxidant, and antitumor properties, which have been verified in animal autoimmune disease models. However, naringenin's possible effects and molecular mechanisms in T cell-mediated autoimmune diseases are unclear. This review summarizes the findings of previous studies and predicts the target of naringenin in T cell-mediated autoimmune disorders such as multiple sclerosis, inflammatory bowel disease, and rheumatoid arthritis through network pharmacology analysis. We performed DAVID enrichment analysis, protein-protein interaction analysis, and molecular docking to predict the positive effect of naringenin on T cell-mediated autoimmune disorders. Sixteen common genes were screened, among which the core genes were PTGS2, ESR1, CAT, CASP3, MAPK1, and AKT1. The possible molecular mechanism relates to HIF-1, estrogen, TNF, and NF-κB signaling pathways. Our findings have significance for future naringenin treatment of T cell-mediated autoimmune diseases.

Interleukin-7-dependent nonclassical monocytes and CD40 expression are affected in children with type 1 diabetes

The important role of IL-7 in the generation of self-reactive T-cells in autoimmune diseases is well established. Recent studies on autoimmunity-associated genetic polymorphisms indicated that differential IL-7 receptor (IL-7R) expression of monocytes may play a role in the underlying pathogenesis. The relevance of IL-7-mediated monocyte functions in type 1 diabetes remains elusive. In the present study, we characterized monocyte phenotype and IL-7-mediated effects in children with type 1 diabetes and healthy controls with multicolor flow cytometry and t-distributed Stochastic Neighbor-Embedded (t-SNE)-analyses. IL-7R expression of monocytes rapidly increased in vitro and was boosted through LPS. In the presence of IL-7, we detected lower monocyte IL-7R expression in type 1 diabetes patients as compared to healthy controls. This difference was most evident for the subset of nonclassical monocytes, which increased after IL-7 stimulation. t-SNE analyses revealed IL-7-dependent differences in monocyte subset distribution and expression of activation and maturation markers (i.e., HLA-DR, CD80, CD86, CD40). Notably, monocyte CD40 expression increased considerably by IL-7 and CD40/IL-7R co-expression differed between patients and controls. This study shows the unique effects of IL-7 on monocyte phenotype and functions. Lower IL-7R expression on IL-7-induced CD40_high monocytes and impaired IL-7 response characterize monocytes from patients with type 1 diabetes.

STAT3 and STAT5 Targeting for Simultaneous Management of Melanoma and Autoimmune Diseases

Melanoma is a skin cancer which can become metastatic, drug-refractory, and lethal if managed late or inappropriately. An increasing number of melanoma patients exhibits autoimmune diseases, either as pre-existing conditions or as sequelae of immune-based anti-melanoma therapies, which complicate patient management and raise the need for more personalized treatments. STAT3 and/or STAT5 cascades are commonly activated during melanoma progression and mediate the metastatic effects of key oncogenic factors. Deactivation of these cascades enhances antitumor-immune responses, is efficient against metastatic melanoma in the preclinical setting and emerges as a promising targeting strategy, especially for patients resistant to immunotherapies. In the light of the recent realization that cancer and autoimmune diseases share common mechanisms of immune dysregulation, we suggest that the systemic delivery of STAT3 or STAT5 inhibitors could simultaneously target both, melanoma and associated autoimmune diseases, thereby decreasing the overall disease burden and improving quality of life of this patient subpopulation. Herein, we review the recent advances of STAT3 and STAT5 targeting in melanoma, explore which autoimmune diseases are causatively linked to STAT3 and/or STAT5 signaling, and propose that these patients may particularly benefit from treatment with STAT3/STAT5 inhibitors.

The Role of Monocytes and Macrophages in Autoimmune Diseases: A Comprehensive Review

Monocytes (Mo) and macrophages (Mϕ) are key components of the innate immune system and are involved in regulation of the initiation, development, and resolution of many inflammatory disorders. In addition, these cells also play important immunoregulatory and tissue-repairing roles to decrease immune reactions and promote tissue regeneration. Several lines of evidence have suggested a causal link between the presence or activation of these cells and the development of autoimmune diseases. In addition, Mo or Mϕ infiltration in diseased tissues is a hallmark of several autoimmune diseases. However, the detailed contributions of these cells, whether they actually initiate disease or perpetuate disease progression, and whether their phenotype and functional alteration are merely epiphenomena are still unclear in many autoimmune diseases. Additionally, little is known about their heterogeneous populations in different autoimmune diseases. Elucidating the relevance of Mo and Mϕ in autoimmune diseases and the associated mechanisms could lead to the identification of more effective therapeutic strategies in the future.

Portal Venous Blood Circulation Supports Immunosuppressive Environment and Pancreatic Cancer Circulating Tumor Cell Activation

OBJECTIVES

Aggressive spread and liver metastases are predominant features of pancreatic ductal adenocarcinoma (PDAC). This study investigates activation of PDAC circulating tumor cells (CTC) and immunosuppression in the portal venous system.

METHODS

Portal venous and peripheral blood were collected during pancreaticoduodenectomy from patients with PDAC (n = 21) or other non-PDAC pancreatic conditions (n = 20). Circulating tumor cells were isolated by fluorescence-activated cell sorting and characterized for messenger RNA (mRNA) expression and acetylated chromatin encoding K-RAS exon 12 mutation (K-RASmut). Myeloid-derived suppressor cells (MDSC) were identified using flow cytometry.

RESULTS

Pancreatic ductal adenocarcinoma K-RASmut mRNA expression in portal venous blood CTC was significantly elevated compared with preoperative and postoperative peripheral blood (P = 0.0123 and P = 0.0246, respectively). There was no significant variation in total CTC numbers between portal and peripheral blood.Portal venous M-MDSC were elevated compared with peripheral blood in PDAC patients (P = 0.0065). M-MDSC increases correlated with K-RASmut mRNA-expressing CTC present in PDAC portal blood (P < 0.0001).

CONCLUSIONS

Association of MDSC with active CTC in portal venous blood may support immunosuppression within the portal venous circulation to promote PDAC CTC survival.

Increased Blood Levels of Growth Factors, Proinflammatory Cytokines, and Th17 Cytokines in Patients with Newly Diagnosed Type 1 Diabetes

The production of several cytokines could be dysregulated in type 1 diabetes (T1D). In particular, the activation of T helper (Th) type 1 (Th1) cells has been proposed to underlie the autoimmune pathogenesis of the disease, although roles for inflammatory processes and the Th17 pathway have also been shown. Nevertheless, despite evidence for the role of cytokines before and at the onset of T1D, the corresponding findings are inconsistent across studies. Moreover, conflicting data exist regarding the blood cytokine levels in T1D patients. The current study was performed to investigate genetic and autoantibody markers in association with the peripheral blood cytokine profiles by xMap multiplex technology in newly diagnosed young T1D patients and age-matched healthy controls. The onset of young-age T1D was characterized by the upregulation of growth factors, including granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin (IL)-7, the proinflammatory cytokine IL-1β (but not IL-6 or tumor necrosis factor [TNF]-α), Th17 cytokines, and the regulatory cytokines IL-10 and IL-27. Ketoacidosis and autoantibodies (anti-IA-2 and -ZnT8), but not human leukocyte antigen (HLA) genotype, influenced the blood cytokine levels. These findings broaden the current understanding of the dysregulation of systemic levels of several key cytokines at the young-age onset of T1D and provide a further basis for the development of novel immunoregulatory treatments in this disease.

Csf2 and Ptgs2 Epigenetic Dysregulation in Diabetes-prone Bicongenic B6.NODC11bxC1tb Mice

In Type 1 diabetic (T1D) human monocytes, STAT5 aberrantly binds to epigenetic regulatory sites of two proinflammatory genes, CSF2 (encoding granulocyte-macrophage colony-stimulating factor) and PTGS2 (encoding prostaglandin synthase 2/cyclooxygenase 2). Bicongenic B6.NOD C11bxC1tb mice re-create this phenotype of T1D monocytes with only two nonobese diabetic (NOD) Idd subloci (130.8 Mb-149.7 Mb, of Idd5 on Chr 1 and 32.08-53.85 Mb of Idd4.3 on Chr11) on C57BL/6 genetic background. These two Idd loci interact through STAT5 binding at upstream regulatory regions affecting Csf2 (Chr 11) and Ptgs2 (Chr 1) expression. B6.NODC11bxC1tb mice exhibited hyperglycemia and immune destruction of pancreatic islets between 8 and 30 weeks of age, with 12%-22% penetrance. Thus, B6.NODC11bxC1tb mice embody NOD epigenetic dysregulation of gene expression in myeloid cells, and this defect appears to be sufficient to impart genetic susceptibility to diabetes in an otherwise genetically nonautoimmune mouse.

Age-Related Differences in Percentages of Regulatory and Effector T Lymphocytes and Their Subsets in Healthy Individuals and Characteristic STAT1/STAT5 Signalling Response in Helper T Lymphocytes

The dynamic process of the development of the immune system can in itself result in age-related immune malfunctions. In this study, we analysed lymphocyte subsets in the peripheral blood of 60 healthy donors, divided into groups of children, adolescents, and adults, focusing on effector (Teff) and regulatory (Treg) T lymphocytes and STAT1/STAT5 signalling response in helper T lymphocytes (Th) in adults, using flow cytometry. Our results demonstrate a decrease in the percentage of total Tregs and an increase in the percentage of total Teffs with age and a consequential immense increase in the Teff/Treg ratio. The increase of Teffs was most apparent in Th1, Th1Th17, and Th17CD161- subsets. Significant Th lymphocyte STAT1 expression differences were observed between children and adolescents, which were associated with the decrease in activated Tregs. Higher expression of STAT1 was found in FoxP3hi than in FoxP3low Th lymphocytes, while significant IL-2 induced STAT5 phosphorylation differences were found among the subsets of Th lymphocytes in adults. Our study demonstrates age-related changes in circulating Teff and Treg, as well as significant differences in STAT5/STAT1 signalling among FoxP3+ Th lymphocytes, providing new advances in the understanding of immunosenescence.

Myeloid cell dysfunction and the pathogenesis of the diabetic chronic wound

Diabetes can promote a state of chronic inflammation associated with serious complications that are difficult to treat, including ulceration of the lower extremities and chronic wounds. Chronic wounds are often incurable and contribute to both a reduced quality of life for patients and an enormous burden for healthcare services. In diabetes, the inflammatory response early in wound healing is inappropriately amplified and prolonged, leading to the persistent presence in the wound of vastly elevated numbers of dysfunctional, hyperpolarised macrophages that fail to transition to a pro-healing phenotype. Recent evidence suggests that systemic chronic inflammation induces intrinsic defects in monocytes via chromatin modifications that may pre-programme monocytes to a pro-inflammatory phenotype, while the local wound environment inhibits differentiation to a pro-healing phenotype. Current understanding remains incomplete, and careful dissection of how local and systemic inflammation combine to negatively influence myeloid cell development will be key to developing effective therapies aimed at healing the diabetic wound.