IL33/ST2 Axis in Diabetic Kidney Disease: A Literature Review

Bone Marrow-Derived C-Kit+ Cells Improved Inflammatory IL-33/ST-2/ILC2 Axis in the Lung Tissue of Type 2 Diabetic Rats

Inflammation is an essential factor in pulmonary complications of diabetes. Bone marrow (BM)-derived C-kit+ cells have immunomodulatory properties and their transplantation is suggested as a promising strategy for ameliorating diabetes complications. This study evaluated the effect of BM-derived C-kit+ cells on the inflammation signaling pathway in lung tissue of type 2 diabetic male rats. Ten rats were used to extract C-kit cells, and 48 male Wistar rats weighing 180 ± 20 g were randomly divided into four equal groups: (1) Control (Cont), (2) Diabetic (D), (3) Diabetic + C-kit+ cells (D + C-kit pos) intravenously injected 50-µl phosphate buffer saline (PBS) containing 300,000 C-kit+ cells, and (4) Diabetic + C-kit- cells (D + C-kit neg), intravenously injected C-kit- cells. Diabetes induction increased IL-33, ST-2, CD127, and IL-2 levels and decreased IL-10. C-kit+ cell therapy significantly decreased IL-33 and CD127 and increased IL-10. In addition, lung histopathological changes significantly improved in the C-kit+ group compared to the diabetic group. These findings suggest that C-kit+ cells may have a potential therapeutic role in mitigating diabetes-induced respiratory complications via ameliorating the inflammation and histopathological changes in lung tissue.

Relationship between the serum level, polymorphism and gene expression of IL-33 in samples of recurrent miscarriage Iraqi women infected with toxoplasmosis

One of the many warm-blooded hosts that toxoplasmosis-causing intracellular protozoan parasite Toxoplasma gondii can infect is humans. Cytokines are crucial to stimulate an effective immune response against T. gondii. Interleukin-33 (IL-33) is a unique anti-inflammatory cytokine that suppresses the immune response. The levels of cytokine gene expression are regulated by genetics, and the genetic polymorphisms of these cytokines play a functional role in this process. Single nucleotide polymorphisms (SNPs) are prognostic indicators of illnesses. This study aimed to determine whether toxoplasmosis interacts with serum levels of IL-33 and its SNP in miscarriage women as well as whether serum levels and IL-33 gene expression are related in toxoplasmosis-positive miscarriage women. Two hundred blood samples from patients and controls were collected from AL-Alawiya Maternity Teaching Hospital and AL-Yarmouk Teaching Hospital in Baghdad, Iraq from 2021 to 2022 in order to evaluate the serum level of IL-33 using ELISA test. For the SNP of IL-33, the allelic high-resolution approach was utilized, and real time-PCR was performed to assess gene expression. The results showed that compared to healthy and pregnant women, recurrent miscarriage with toxoplasmosis and recurrent miscarriage women had lower IL-33 concentrations. Additionally, there were significant differences among healthy women, pregnant women, and women with repeated miscarriage who experienced toxoplasmosis. Furthermore, no differences between patients and controls were revealed by gene expression data. The results revealed that recurrent miscarriage, pregnancy, and healthy women all had a slightly higher amount of the IL-33 gene fold. Additionally, the SNP of IL-33 data demonstrated that there was no significant genetic relationship between patients and controls. Recurrent miscarriage women with toxoplasmosis have showed significant differences from pregnant women in the genotypes GG and AA as well as the alleles A and G. There were notable variations between recurrent miscarriage with and without toxoplasmosis in terms of the genotypes AA and AC. The genotypes GG, AA, and allele A in recurrent miscarriage women with toxoplasmosis and recurrent miscarriage women is a protective factor. Taking together, there was a statistically significant negative correlation between toxoplasmosis and IL-33 gene expression, which calls for more quantitative investigation in order to fully comprehend the interaction of mRNA and protein.

A biomarker for bacteremia in pregnant women with acute pyelonephritis: soluble suppressor of tumorigenicity 2 or sST2

Objective: Sepsis is a leading cause of maternal death, and its diagnosis during the golden hour is critical to improve survival. Acute pyelonephritis in pregnancy is a risk factor for obstetrical and medical complications, and it is a major cause of sepsis, as bacteremia complicates 15-20% of pyelonephritis episodes in pregnancy. The diagnosis of bacteremia currently relies on blood cultures, whereas a rapid test could allow timely management and improved outcomes. Soluble suppression of tumorigenicity 2 (sST2) was previously proposed as a biomarker for sepsis in non-pregnant adults and children. This study was designed to determine whether maternal plasma concentrations of sST2 in pregnant patients with pyelonephritis can help to identify those at risk for bacteremia.Study design: This cross-sectional study included women with normal pregnancy (n = 131) and pregnant women with acute pyelonephritis (n = 36). Acute pyelonephritis was diagnosed based on a combination of clinical findings and a positive urine culture. Patients were further classified according to the results of blood cultures into those with and without bacteremia. Plasma concentrations of sST2 were determined by a sensitive immunoassay. Non-parametric statistics were used for analysis.Results: The maternal plasma sST2 concentration increased with gestational age in normal pregnancies. Pregnant patients with acute pyelonephritis had a higher median (interquartile range) plasma sST2 concentration than those with a normal pregnancy [85 (47-239) ng/mL vs. 31 (14-52) ng/mL, p < .001]. Among patients with pyelonephritis, those with a positive blood culture had a median plasma concentration of sST2 higher than that of patients with a negative blood culture [258 (IQR: 75-305) ng/mL vs. 83 (IQR: 46-153) ng/mL; p = .03]. An elevated plasma concentration of sST2 ≥ 215 ng/mL had a sensitivity of 73% and a specificity of 95% (area under the receiver operating characteristic curve, 0.74; p = .003) with a positive likelihood ratio of 13.8 and a negative likelihood ratio of 0.3 for the identification of patients who had a positive blood culture.Conclusion: sST2 is a candidate biomarker to identify bacteremia in pregnant women with pyelonephritis. Rapid identification of these patients may optimize patient care.

Tozorakimab (MEDI3506): an anti-IL-33 antibody that inhibits IL-33 signalling via ST2 and RAGE/EGFR to reduce inflammation and epithelial dysfunction

Interleukin (IL)-33 is a broad-acting alarmin cytokine that can drive inflammatory responses following tissue damage or infection and is a promising target for treatment of inflammatory disease. Here, we describe the identification of tozorakimab (MEDI3506), a potent, human anti-IL-33 monoclonal antibody, which can inhibit reduced IL-33 (IL-33red) and oxidized IL-33 (IL-33ox) activities through distinct serum-stimulated 2 (ST2) and receptor for advanced glycation end products/epidermal growth factor receptor (RAGE/EGFR complex) signalling pathways. We hypothesized that a therapeutic antibody would require an affinity higher than that of ST2 for IL-33, with an association rate greater than 107 M-1 s-1, to effectively neutralize IL-33 following rapid release from damaged tissue. An innovative antibody generation campaign identified tozorakimab, an antibody with a femtomolar affinity for IL-33red and a fast association rate (8.5 × 107 M-1 s-1), which was comparable to soluble ST2. Tozorakimab potently inhibited ST2-dependent inflammatory responses driven by IL-33 in primary human cells and in a murine model of lung epithelial injury. Additionally, tozorakimab prevented the oxidation of IL-33 and its activity via the RAGE/EGFR signalling pathway, thus increasing in vitro epithelial cell migration and repair. Tozorakimab is a novel therapeutic agent with a dual mechanism of action that blocks IL-33red and IL-33ox signalling, offering potential to reduce inflammation and epithelial dysfunction in human disease.

Network-Based Assessment of Minimal Change Disease Identifies Glomerular Response to IL-7 and IL-12 Pathways Activation as Innovative Treatment Target

Background: Minimal change disease (MCD), a major cause of nephrotic syndrome, is usually treated by corticosteroid administration. MCD unresponsiveness to therapy and recurrences are nonetheless frequently observed, particularly in adults. To explore MCD-related pathogenetic mechanisms and to identify novel drug targets ultimately contributing to novel therapeutic avenues with a certain specificity for MCD, we compared glomerular transcriptomes from MCD with membranous nephropathy (MN) patients and healthy controls. Methods: Renal biopsies from adult patients with MCD (n = 14) or MN (n = 12), and non-diseased controls (n = 8) were selected from the Norwegian Kidney Biopsy Registry. RNA for 75 base-pair paired-end RNASeq were obtained from laser capture micro-dissected (LCM) glomeruli from FFPE sections. Transcriptional landscapes were computed by combining pathway-centered analyses and network science methodologies that integrate multiple bioinformatics resources. Results: Compared to normal glomeruli, cells from MCD displayed an inflammatory signature apparently governed by the IL1 and IL7 systems. While enrichment of IL1 production and secretion was a shared feature of MCD and MN compared to normal tissue, responses involving IL7 pathway activation were unique to MCD. Indeed, IL7R expressed by glomeruli was the most upregulated gene of the interleukin family in MCD versus normal controls. IL7 pathway activation was paralleled by significant enrichment in adaptive immune system processes and transcriptional regulation and depletion in pathways related to energy metabolism and transcription. Downregulation of these organ function-related themes again occurred predominately in MCD and was significantly less pronounced in MN. Immunofluorescence and immunohistochemistry, respectively, confirmed the expression of phosphorylated IL-7 receptor alpha (IL7RA, CD127) and IL12 receptor beta 1 (IL12RB1) proteins. Conclusions: Gene expression profiling of archival FFPE-biopsies identifies MCD-specific signatures with IL7RA and IL12RB1 as novel targets for MCD treatment.

Evaluation of Subclinical Vascular Disease in Diabetic Kidney Disease: A Tool for Personalization of Management of a High-Risk Population

Background: Patients with diabetic kidney disease (DKD) are at increased risk for cardiovascular events but traditional risk factors do not fully explain this association. Evaluation of subclinical vascular disease might improve risk stratification and management of these patients. The aim of the study was to compare the prevalence of markers of arterial stiffness, carotid atherosclerosis and peripheral arterial disease between patients with DKD and patients with type 2 diabetes mellitus (T2DM) and preserved kidney function. Methods: We prospectively enrolled patients with DKD and age- and gender-matched patients with T2DM but without DKD (estimated glomerular filtration rate < and ≥60 mL/min/1.73 m2, respectively). The presence of arterial stiffness was evaluated by measuring pulse wave velocity (PWV), augmentation index (AIx), AIx adjusted to a heart rate of 75 beats/min (AIx@75) and central systolic, diastolic, pulse and mean blood pressure. The presence of carotid atherosclerosis was evaluated by measuring carotid stenosis, carotid intima-media thickness and maximal plaque thickness. The presence of PAD was evaluated with the measurement of ankle-brachial index (ABI). Results: Forty patients with T2DM were included in the study (mean age 71.6 ± 8.9 years). The prevalence of cardiovascular risk factors was similar in patients with and without DKD. PWV was higher in the former (9.8 ± 5.5 and 6.6 ± 4.4 m/s, respectively; p < 0.05) and carotid stenosis of the left carotid artery was also greater in patients with DKD (36.5 ± 12.6 and 22.1 ± 17.2%, respectively; p < 0.05). Other markers of arterial stiffness and carotid atherosclerosis and ABI did not differ between patients with DKD and those without DKD. Conclusions: Patients with DKD appear to have more pronounced arterial stiffness and carotid atherosclerosis than patients with T2DM and preserved kidney function despite the similar prevalence of traditional cardiovascular risk factors in the two groups. Therefore, evaluating the presence of subclinical vascular disease in these patients could be a useful tool for the personalization of their management.

IL33 and sST2 serum level in systemic sclerosis microvascular involvement

AIM

Endothelial dysfunction and microvascular damage are hallmarks of systemic sclerosis (SSc). Objective of this study was to evaluate IL33 and ST2 serum levels in SSc patients and healthy controls (HC). Secondary aim was to evaluate the IL33 axis in the SSc microvascular manifestation.

METHODS

IL33 and sST2 have been assessed in 46 SSc patients and 24 HC matched for sex and age. Main clinimetric indexes were assessed. Skin perfusion of hands was evaluated by Laser Speckle Contrast Analysis (LASCA) and echocolordoppler ultrasound of renal arteries was performed to evaluate subclinical renal involvement.

RESULTS

SSc patients had higher serum level of IL33 and sST2 than HC. IL33 and sST2 were significantly higher in SSc patient with digital ulcers (DUs) compared to SSc patients without DUs. SSc patients with late nailfold videocapillaroscopy (NVC) pattern had higher serum levels of sST2 than SSc patients with active NVC pattern. SSc patients without proximal-distal gradient (PDG) at LASCA had significantly higher sST2 serum level compared to SSc patients with PDG. SSc patients with renal resistive index (RRI) ≥ 0.70 had higher serum levels of sST2 than SSc patients with RRI < 0.70. A positive linear correlation was shown between sST2 and RRI, between sST2 and intrarenal S/D and between sST2 and PI. Kaplan-Meier curves show a significantly reduced free survival from DUs in patients with increased sST2 (p = 0.025). In multivariate analysis, sST2 is associated with the development of new DUs.

CONCLUSION

IL33 and sST2 are increased in SSc patients and ST2 might be a marker of microvascular damage.

Interleukin-33/ Suppression of Tumorigenicity 2 in Renal Fibrosis: Emerging Roles in Prognosis and Treatment

Chronic kidney disease (CKD) is a major public health problem that affects more than 10% of the population worldwide and has a high mortality rate. Therefore, it is necessary to identify novel treatment strategies for CKD. Incidentally, renal fibrosis plays a central role in the progression of CKD to end-stage renal disease (ESRD). The activation of inflammatory pathways leads to the development of renal fibrosis. In fact, interleukin-33 (IL-33), a newly discovered member of the interleukin 1 (IL-1) cytokine family, is a crucial regulator of the inflammatory process. It exerts pro-inflammatory and pro-fibrotic effects via the suppression of tumorigenicity 2 (ST2) receptor, which, in turn, activates other inflammatory pathways. Although the role of this pathway in cardiac, pulmonary, and hepatic fibrotic diseases has been extensively studied, its precise role in renal fibrosis has not yet been completely elucidated. Recent studies have shown that a sustained activation of IL-33/ST2 pathway promotes the development of renal fibrosis. However, with prolonged research in this field, it is expected that the IL-33/ST2 pathway will be used as a diagnostic and prognostic tool for renal diseases. In addition, the IL-33/ST2 pathway seems to be a new target for the future treatment of CKD. Here, we review the mechanisms and potential applications of the IL-33/ST2 pathway in renal fibrosis; such that it can help clinicians and researchers to explore effective treatment options and develop novel medicines for CKD patients.

Interleukin-33 and its receptor soluble suppression of tumorigenicity 2 in the diagnosis of gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) is the most common pregnancy-related disease that increases the risk of metabolic disorders for the pregnancies and their offspring. GDM could be effectively prevented by early diagnosis and timely treatment.

METHODS

120 patients with GDM and 108 gestational week-matched pregnancies with normal glucose tolerance (NGT) were enrolled in our study. Their blood samples were collected, and demographic characteristics were analysed.

RESULTS

Compared to NGT pregnancies, patients with GDM had increased the secretions of interleukin (IL)-33, soluble suppression of tumorigenicity 2 (sST2), IL-6 and tumour necrosis factor-α (TNF-α) in their plasma with elevated homeostatic model assessment (HOMA). Moreover, IL-33/sST2 was positively correlated with HOMA, IL-6 and TNF-α levels in the plasma of patients with GDM respectively.

CONCLUSION

IL-33/sST2 might serve as a novel potential biomarker for early diagnosis of GDM.

Phenethyl isothiocyanate attenuates diabetic nephropathy via modulation of glycative/oxidative/inflammatory signaling in diabetic rats

Diabetic nephropathy (DN) is a diabetic complication characterized by disruption of renal microvasculature, reactive oxygen species accumulation and increased inflammation, all of which contribute to renal injury. Phenethyl isothiocyanate (PEITC) is a naturally occurring isothiocyanate well known for its antioxidant and anti-inflammatory effects, yet its reno-preventive effects against DN has not been investigated. The current study looked into the in vivo reno-protective effects of PEITC in STZ-induced DN in rats. PEITC (3, 10 and 30 mg/kg) was administered orally for 8 weeks post DM establishment. PEITC treatment significantly improved kidney and liver functions, renal histopathological features, tissue fibrosis, macrophage infiltration and blood glucose levels compared to DN control. Mechanistically, PEITC treatment alleviated DN-induced renal damage via modulating glycation and oxidative stresses and inflammatory response. As such, PEITC activated glyoxalase 1 (GLO1) that induced a retraction in renal tissue expression of advanced glycation end products (AGEs) and its receptor (RAGE). PEITC activated nuclear erythroid 2-related factor 2 (Nrf2) and increased expression of its downstream targets, hemeoxygenase-1 (HO-1) and gamma glutamate-cysteine (γ-GCS). Additionally, PEITC treatment decreased the expression of Nrf2 repressor protein, keap1. The anti-inflammatory effect of PEITC was driven, at least in part, via reducing the NLRP3 inflammasome activation as indicated by down regulation of NLRP3, TXNIP, capsase-1 and IL-1β, TNF-alpha and IL-6. In conclusion; PEITC attenuated DN progression in a dose dependent manner mainly via interruption of AGE/RAGE and NLPR3/TXNIP/NrF2 crosstalk.

Expression and significance of inflammatory reactions mediated by the IL-33/ST2 signaling pathway in the serum of heart failure patients

OBJECTIVE

This research aimed to explore the clinical significance of inflammatory reactions mediated by the IL-33/ST2 signaling pathway in heart failure (HF) patients.

METHODS

A total of 100 HF patients treated in the Department of Cardiology in our hospital were prospectively regarded as the observation group, and 100 healthy age and gender matched patients who were undergoing physical examination were considered as the control group. The levels of interleukin-33 (IL-33), ST2, tumor necrosis factor-α (TNF-α) and pro B-type natriuretic peptide (pro-BNP) in the peripheral blood of patients were detected. The potential correlation between IL-33 and ST2, TNF-α and pro-BNP was analyzed by Pearson.

RESULTS

The levels of IL-33, IL-10, ST2 and pro-BNP in the peripheral blood of patients in the observation group were higher than those in the control group; and they increased with the rise of cardiac function grade (all P<0.05). In addition, IL-33 was positively correlated with TNF-α, ST2 and pro-BNP (r=0.863, 0.879, 0.945; all P<0.05). Multivariate Logistic analysis revealed that the increase of IL-33 and ST2 were independent risk factors of HF.

CONCLUSION

The IL-33 and ST2 levels in the peripheral serum of HF patients are correlated with TNF-α and BNP, the finding of which can assist in clinical diagnosis and treatment.

The IL-33/ST2 Axis in Immune Responses Against Parasitic Disease: Potential Therapeutic Applications

Parasitic infections pose a wide and varying threat globally, impacting over 25% of the global population with many more at risk of infection. These infections are comprised of, but not limited to, toxoplasmosis, malaria, leishmaniasis and any one of a wide variety of helminthic infections. While a great deal is understood about the adaptive immune response to each of these parasites, there remains a need to further elucidate the early innate immune response. Interleukin-33 is being revealed as one of the earliest players in the cytokine milieu responding to parasitic invasion, and as such has been given the name "alarmin." A nuclear cytokine, interleukin-33 is housed primarily within epithelial and fibroblastic tissues and is released upon cellular damage or death. Evidence has shown that interleukin-33 seems to play a crucial role in priming the immune system toward a strong T helper type 2 immune response, necessary in the clearance of some parasites, while disease exacerbating in the context of others. With the possibility of being a double-edged sword, a great deal remains to be seen in how interleukin-33 and its receptor ST2 are involved in the immune response different parasites elicit, and how those parasites may manipulate or evade this host mechanism. In this review article we compile the current cutting-edge research into the interleukin-33 response to toxoplasmosis, malaria, leishmania, and helminthic infection. Furthermore, we provide insight into directions interleukin-33 research may take in the future, potential immunotherapeutic applications of interleukin-33 modulation and how a better clarity of early innate immune system responses involving interleukin-33/ST2 signaling may be applied in development of much needed treatment options against parasitic invaders.

Alteration of the IL-33-sST2 pathway in hypertensive patients and a mouse model

Inflammatory cells play an important role in the occurrence of hypertension. Recent studies have demonstrated that interleukin-33/suppression of tumorigenicity 2 (IL-33/ST2) signaling plays a critical role in the pathogenesis of several cardiovascular diseases. We aimed to evaluate the association of IL-33 and its receptor levels with the occurrence of hypertension in angiotensin II (Ang II)-infused mice using microarray analysis and validated our results in human specimens. Male wild-type mice were infused with Ang II (1500 ng/kg/min) for 1, 3 and 7 days. Patients with essential hypertension (EH) (n = 166) and healthy control subjects (n = 306) were enrolled. Levels of IL-33 and ST2 mRNAs in serum and peripheral blood mononuclear cells (PBMCs) were analyzed by Luminex assay or ELISA and qPCR analysis. We found that IL-33 expression was significantly increased in the aortas of mice receiving Ang II infusion compared with that of control mice. In contrast, the levels of IL-33 in serum and PBMCs were not significantly different between hypertensive patients and normal controls. However, the levels of soluble ST2 (sST2) in serum and PBMCs were markedly higher in hypertensive patients than in controls (P < 0.001 and P = 0.014, respectively). In addition, the ST2L level in PBMCs was also significantly decreased in hypertensive patients (P = 0.028). Further, logistic analysis showed that the odds ratios of having hypertension based on sST2 levels in serum and PBMCs were 9.714 and 2.244 (P = 0.013 and P = 0.024, respectively) compared with the control group. Above all, sST2 acted as a risk factor for the occurrence of hypertension and may be a promising novel predictive marker for EH.

Lysophosphatidic Acid Signaling in Diabetic Nephropathy

Lysophosphatidic acid (LPA) is a bioactive phospholipid present in most tissues and body fluids. LPA acts through specific LPA receptors (LPAR1 to LPAR6) coupled with G protein. LPA binds to receptors and activates multiple cellular signaling pathways, subsequently exerting various biological functions, such as cell proliferation, migration, and apoptosis. LPA also induces cell damage through complex overlapping pathways, including the generation of reactive oxygen species, inflammatory cytokines, and fibrosis. Several reports indicate that the LPA–LPAR axis plays an important role in various diseases, including kidney disease, lung fibrosis, and cancer. Diabetic nephropathy (DN) is one of the most common diabetic complications and the main risk factor for chronic kidney diseases, which mostly progress to end-stage renal disease. There is also growing evidence indicating that the LPA–LPAR axis also plays an important role in inducing pathological alterations of cell structure and function in the kidneys. In this review, we will discuss key mediators or signaling pathways activated by LPA and summarize recent research findings associated with DN.