Could IL-17A Be a Novel Therapeutic Target in Diabetic Nephropathy?

IL-17 in type II diabetes mellitus (T2DM) immunopathogenesis and complications; molecular approaches

Chronic inflammation has long been considered the characteristic feature of type II diabetes mellitus (T2DM) Immunopathogenesis. Pro-inflammatory cytokines are considered the central drivers of the inflammatory cascade leading to β-cell dysfunction and insulin resistance (IR), two major pathologic events contributing to T2DM. Analyzing the cytokine profile of T2DM patients has also introduced interleukin-17 (IL-17) as an upstream regulator of inflammation, regarding its role in inducing the nuclear factor-kappa B (NF-κB) pathway. In diabetic tissues, IL-17 induces the expression of inflammatory cytokines and chemokines. Hence, IL-17 can deteriorate insulin signaling and β-cell function by activating the JNK pathway and inducing infiltration of neutrophils into pancreatic islets, respectively. Additionally, higher levels of IL-17 expression in patients with diabetic complications compared to non-complicated individuals have also proposed a role for IL-17 in T2DM complications. Here, we highlight the role of IL-17 in the Immunopathogenesis of T2DM and corresponding pathways, recent advances in preclinical and clinical studies targeting IL-17 in T2DM, and corresponding challenges and possible solutions.

Identification and validation of voltage-dependent anion channel 1-related genes and immune cell infiltration in diabetic nephropathy

AIMS/INTRODUCTION

This study investigated the roles of voltage-dependent anion channel 1-related differentially expressed genes (VRDEGs) in diabetic nephropathy (DN).

MATERIALS AND METHODS

We downloaded two datasets from patients with DN, namely, GSE30122 and GSE30529, from the Gene Expression Omnibus database. VRDEGs associated with DN were obtained from the intersection of voltage-dependent anion channel 1-related genes from the GeneCards database, and differentially expressed genes were screened according to group (DN/healthy) in the two datasets. The enriched pathways of the VRDEGs were analyzed. Hub genes were selected using a protein-protein interaction network, and their predictive value was verified through receiver operating characteristic curve analysis. The CIBERSORTx software examined hub genes and immune cell infiltration associations. The protein expression of hub genes was verified through immunohistochemistry in 16-week-old db/db mice for experimentation as a model of type 2 DN. Finally, potential drugs targeting hub genes that inhibit DN development were identified.

RESULTS

A total of 57 VRDEGs were identified. The two datasets showed high expression of the PI3K, Notch, transforming growth factor-β, interleukin-10 and interleukin-17 pathways in DN. Five hub genes (ITGAM, B2M, LYZ, C3 and CASP1) associated with DN were identified and verified. Immunohistochemistry showed that the five hub genes were highly expressed in db/db mice, compared with db/m mice. The infiltration of immune cells was significantly correlated with the five hub genes.

CONCLUSIONS

Five hub genes were significantly correlated with immune cell infiltration and might be crucial to DN development. This study provides insight into the mechanisms involved in the pathogenesis of DN.

Dysregulated miRNA-375, IL-17, TGF-β, and Microminerals Are Associated with Calpain-10 SNP 19 in Diabetic Patients: Correlation with Diabetic Nephropathy Stages

Zinc (Zn) and copper (Cu) have been shown to have the potential to improve glucose metabolism through interactions with cytokines and signaling events with multiple genes. miRNA-375 and the Calpin-10 gene are potential genetic biomarkers for the early prediction of diabetic nephropathy (DN). 128 healthy controls and 129 type 2 diabetic (T2DM) participants were matched for age and sex. Three subgroups were identified from the T2DM group: 39 patients had microalbuminuria, 41 had macroalbuminuria, and 49 patients had renal problems. Circulating miR-375 expression levels were measured via qPCR. Calpain-10 SNP 19 (rs3842570) genotyping was assessed with allele-specific PCR in all the included participants. Spectrophotometry was used to measure the concentrations of serum copper, zinc, and magnesium, while ELISA was used to measure the levels of TGF-β and IL-17. There was significant up-regulation in the expression of miR-375 and serum levels of TGF-β, IL-17, Cu, and the Cu/Zn ratio, whereas, in contrast to the control group, the Zn and Mg levels were lower in the T2DM group. The DN groups had significantly lower miR-375, TGF-β, IL-17, Mg, and Zn levels compared with the T2DM without nephropathy group. Furthermore, between TGF-β, IL-17, and miRNA-375, there were notable correlations. Calpain-10 SNP 19 genotype 22 and allele 2 were linked to a higher incidence of T2DM and DN. Significant TGF-β, Cu, Cu/Zn ratio, HbAc1, and creatinine levels, but insignificant miRNA-375 levels, were associated with genotype 22 of Calpain-10 SNP 19. interactions between the Calpain-10 SNP 19 genotype 22 and IL-17, TGF-β, mineral levels, and miRNA-375 might contribute to the aetiology of DN and T2DM and may have clinical implications for diagnosis and management.

Jiangtang Decoction Ameliorates Diabetic Kidney Disease Through the Modulation of the Gut Microbiota

Purpose

This study aimed to elucidate the impact of Jiangtang decoction (JTD) on diabetic kidney disease (DKD) and its association with alterations in the gut microbiota.

Methods

Using a diabetic mouse model (KK-Ay mice), daily administration of JTD for eight weeks was undertaken. Weekly measurements of body weight and blood glucose were performed, while kidney function, uremic toxins, inflammation factors, and fecal microbiota composition were assessed upon sacrifice. Ultra-structural analysis of kidney tissue was conducted to observe the pathological changes.

Results

The study findings demonstrated that JTD improve metabolism, kidney function, uremic toxins and inflammation, while also exerting a modulatory effect on the gut microbiota. Specifically, the genera Rikenella, Lachnoclostridium, and unclassified_c_Bacilli exhibited significantly increased abundance following JTD treatment, accompanied by reduced abundance of norank_f_Lachnospiraceae compared to the model group. Importantly, Rikenella and unclassified_c_Bacilli demonstrated negative correlations with urine protein levels. Lachnoclostridium and norank_f_Lachnospiraceae were positively associated with creatinine (Cr), indoxyl sulfate (IS) and interleukin (IL)-6. Moreover, norank_f_Lachnospiraceae exhibited positive associations with various indicators of DKD severity, including weight, blood glucose, urea nitrogen (UN), kidney injury molecule-1 (KIM-1) levels, trimethylamine-N-oxide (TMAO), p-cresyl sulfate (pCS), nucleotide-binding oligomerization domain (Nod)-like receptor family pyrin domain-containing 3 (NLRP3) and IL-17A production.

Conclusion

These findings suggested that JTD possess the ability to modulate the abundance of Rikenella, Lachnoclostridium, unclassified_c_Bacilli and norank_f_Lachnospiraceae within the gut microbiota. This modulation, in turn, influenced metabolic processes, kidney function, uremic toxin accumulation, and inflammation, ultimately contributing to the amelioration of DKD.

The roles of interleukin-17A in risk stratification and prognosis of patients with sepsis-associated acute kidney injury

BACKGROUND

The aim of this study was to evaluate the roles of interleukin (IL)-17A in risk stratification and prognosis of patients with sepsis-associated acute kidney injury (SAKI).

METHODS

We enrolled 146 sepsis patients (84 non-SAKI and 62 SAKI patients) admitted to the emergency department from November 2020 to November 2021. Patients with SAKI were differentiated based on the severity of acute kidney injury. All clinical parameters were evaluated upon admission before administering antibiotic treatment. Inflammatory cytokines were assessed using flow cytometry and the Pylon 3D automated immunoassay system (ET Healthcare). In addition, a receiver operating characteristic (ROC) curve was utilized to determine the prognostic values of IL-17A in SAKI.

RESULTS

The levels of creatinine, IL-2, IL-4, IL-6, IL-17A, tumor necrosis factor alpha, C-reactive protein, and procalcitonin (PCT) were significantly higher in the SAKI group than in the non-SAKI group (p < 0.05). The level of IL-17A revealed significant differences among stages 1, 2, and 3 in SAKI patients (p < 0.05). The mean levels of PCT, IL-4, and IL-17A were significantly higher in the non-survival group than in the survival group in SAKI patients (p < 0.05). In addition, the area under the ROC curve of IL-17A was 0.811. Moreover, the IL-17A cutoff for differentiating survivors from non-survivors was 4.7 pg/mL, of which the sensitivity and specificity were 77.4% and 71.0%, respectively.

CONCLUSION

Elevated levels of IL-17A could predict that SAKI patients are significantly prone to worsening kidney injury with higher mortality. The usefulness of IL-17A in treating SAKI requires further research.

Identification of key genes and biological regulatory mechanisms in diabetic nephropathy: Meta-analysis of gene expression datasets

BACKGROUND

Diabetic nephropathy (DN) which refers to the cases with biopsy proven kidney lesions, is one of the main complications of diabetes all around the world; however, the underlying biological changes causing DN remain to be understood. Studying the alterations in gene expression profiles could give a holistic view of the molecular pathogenicity of DN and aid to discover key molecules as potential therapeutic targets. Here, we performed a meta-analysis study that included microarray gene expression profiles coming from glomerular samples of DN patients in order to acquire a list of consensus Differentially Expressed Genes (meta-DEGs) correlated with DN.

METHODS

After quality control and normalization steps, five gene expression datasets (GES1009, GSE30528, GSE47183, GSE104948, and GSE93804) were entered into the meta-analysis. The meta-analysis was performed by random effect size method and the meta-DEGs were put through network analysis and different pathway enrichment analyses steps. MiRTarBase and TRRUST databases were utilized to predict the meta-DEGs related miRNAs and transcription factors. A co-regulatory network including DEGs, transcription factors and miRNAs was constructed by Cytoscape, and top molecules were identified based on centrality scores in the network.

RESULTS

The identified meta-DEGs were 1364 DEGs including 665 downregulated and 669 upregulated DEGs. The results of pathway enrichment analysis showed, "immune system", "extracellular matrix organization", "hemostasis", "signal transduction", and "platelet activation" to be the top enriched terms with involvement of the meta-DEGs. After construction of the multilayer regulatory network, several top DEGs (TP53, MYC, BTG2, VEGFA, PTEN, etc.), as well as top miRNAs (miR-335, miR-16, miR-17, miR-20a, and miR-93), and transcription factors (SP1, STAT3, NF-KB1, RELA, E2F1), were introduced as potential therapeutic targets in DN. Among the regulatory molecules, miR-335-5p and SP1 were the most interactive miRNA and transcription factor molecules with the highest degree scores in the constructed network.

CONCLUSION

By performing a meta-analysis of available DN-related transcriptomics datasets, we reached a consensus list of DEGs for this complicated disorder. Further enrichment and network analyses steps revealed the involved pathways in the DN pathogenesis and marked the most potential therapeutic targets in this disease.

Diabetic complications and prospective immunotherapy

The incidence of Diabetes Mellitus is increasing globally. Individuals who have been burdened with diabetes for many years often develop complications as a result of hyperglycemia. More and more research is being conducted highlighting inflammation as an important factor in disease progression. In all kinds of diabetes, hyperglycemia leads to activation of alternative glucose metabolic pathways, resulting in problematic by-products including reactive oxygen species and advanced glycation end products. This review takes a look into the pathogenesis of three specific diabetic complications; retinopathy, nephropathy and neuropathy as well as their current treatment options. By considering recent research papers investigating the effects of immunotherapy on relevant conditions in animal models, multiple strategies are suggested for future treatment and prevention of diabetic complications with an emphasis on molecular targets associated with the inflammation.

Clinical significance of Interleukin 17 receptor E in diabetic nephropathy

OBJECTIVE

Diabetic nephropathy (DN) is a leading cause of end-stage renal disease. Since there are limited therapeutic options available for the prevention of DN progression, it is imperative to explore novel differentially expressed genes and therapeutic targets for DN.

METHODS

In this study, mice kidney tissue were subjected to transcriptome sequencing and the results were analysed using bioinformatics methods. Interleukin 17 receptor E (IL-17RE) was screened from the sequencing data and its expression was validated in the animal tissues and a cross-sectional clinical study. Fifty-five DN patients were enrolled and further subdivided into two groups based on the urinary albumin-to-creatinine ratio (UACR). Two control groups were used for comparison (minimal change disease group, 12 patients; normal control group, 6 patients). Correlation analysis was conducted to study the relationship between IL-17RE expression and the clinicopathological indices. Logistic regression and receiver operating characteristic (ROC) curve analyses were conducted to evaluate the diagnostic value.

RESULTS

IL-17RE expression was significantly higher in db/db mice and the kidney tissues of DN patients than the control group. IL-17RE protein levels in the kidney tissues were strongly correlated with neutrophil gelatinase-associated lipocalin (NGAL) levels, UACR, and certain clinicopathological indices. IL-17RE levels, total cholesterol (TC) levels, and glomerular lesions were independent risk factors for macroalbuminuria. ROC curves showed a good detection value for IL-17RE in macroalbuminuria (area under the curve = 0.861).

CONCLUSION

The results of this study provide novel insights into DN pathogenesis. Kidney IL-17RE expression levels were associated with DN disease severity and albuminuria.

Novel Aspects of the Immune Response Involved in the Peritoneal Damage in Chronic Kidney Disease Patients under Dialysis

Chronic kidney disease (CKD) incidence is growing worldwide, with a significant percentage of CKD patients reaching end-stage renal disease (ESRD) and requiring kidney replacement therapies (KRT). Peritoneal dialysis (PD) is a convenient KRT presenting benefices as home therapy. In PD patients, the peritoneum is chronically exposed to PD fluids containing supraphysiologic concentrations of glucose or other osmotic agents, leading to the activation of cellular and molecular processes of damage, including inflammation and fibrosis. Importantly, peritonitis episodes enhance peritoneum inflammation status and accelerate peritoneal injury. Here, we review the role of immune cells in the damage of the peritoneal membrane (PM) by repeated exposure to PD fluids during KRT as well as by bacterial or viral infections. We also discuss the anti-inflammatory properties of current clinical treatments of CKD patients in KRT and their potential effect on preserving PM integrity. Finally, given the current importance of coronavirus disease 2019 (COVID-19) disease, we also analyze here the implications of this disease in CKD and KRT.

Targeting inflammation to treat diabetic kidney disease: the road to 2030

Diabetic kidney disease (DKD) is one of the fastest growing causes of chronic kidney disease and associated morbidity and mortality. Preclinical research has demonstrated the involvement of inflammation in its pathogenesis and in the progression of kidney damage, supporting clinical trials designed to explore anti-inflammatory strategies. However, the recent success of sodium-glucose cotransporter-2 inhibitors and the nonsteroidal mineralocorticoid receptor antagonist finerenone has changed both guidelines and standard of care, rendering obsolete older studies directly targeting inflammatory mediators and the clinical development was discontinued for most anti-inflammatory drugs undergoing clinical trials for DKD in 2016. Given the contribution of inflammation to the pathogenesis of DKD, we review the impact on kidney inflammation of the current standard of care, therapies undergoing clinical trials, or repositioned drugs for DKD. Moreover, we review recent advances in the molecular regulation of inflammation in DKD and discuss potential novel therapeutic strategies with clinical relevance. Finally, we provide a road map for future research aimed at integrating the growing knowledge on inflammation and DKD into clinical practice to foster improvement of patient outcomes.

Anti-IL17A Halts the Onset of Diabetic Retinopathy in Type I and II Diabetic Mice

There are ~463 million diabetics worldwide, and more than half have diabetic retinopathy. Yet, treatments are still lacking for non-proliferative diabetic retinopathy. We and others previously provided evidence that Interleukin-17A (IL-17A) plays a pivotal role in non-proliferative diabetic retinopathy. However, all murine studies used Type I diabetes models. Hence, it was the aim of this study to determine if IL-17A induces non-proliferative diabetic retinopathy in Type II diabetic mice, as identified for Type I diabetes. While examining the efficacy of anti-IL-17A as a potential therapeutic in a short-term Type I and a long-term Type II diabetes model; using different routes of administration of anti-IL-17A treatments. Retinal inflammation was significantly decreased (p < 0.05) after Type I-diabetic mice received 1 intravitreal injection, and Type II-diabetic mice received seven intraperitoneal injections of anti-IL-17A. Further, vascular tight junction protein Zonula Occludens-1 (ZO-1) was significantly decreased in both Type I and II diabetic mice, which was significantly increased when mice received anti-IL-17A injections (p < 0.05). Similarly, tight junction protein Occludin degradation was halted in Type II diabetic mice that received anti-IL-17A treatments. Finally, retinal capillary degeneration was halted 6 months after diabetes was confirmed in Type II-diabetic mice that received weekly intraperitoneal injections of anti-IL-17A. These findings provide evidence that IL-17A plays a pivotal role in non-proliferative diabetic retinopathy in Type II diabetic mice, and suggests that anti-IL-17A could be a good therapeutic candidate for non-proliferative diabetic retinopathy.

IL-17A in diabetic kidney disease: protection or damage

The effect of IL-17A in diabetic kidney disease (DKD) has received increasing attention. Interleukin (IL)-17A promotes renal inflammation and the progression of DKD, and IL-17A deficiency improves experimental DKD. However, recent studies have found that the effect of IL-17A on DKD is more complicated than the negative impact. IL-17A alleviates renal inflammation and fibrosis via regulating autophagy or the macrophage phenotype. Moreover, paradoxical expression of IL-17A has been reported in human DKD. This review focuses on how IL-17A affects the progression of DKD and the resulting opportunities and challenges.

Kidney microRNA Expression Pattern in Type 2 Diabetic Nephropathy in BTBR Ob/Ob Mice

Diabetic nephropathy (DN) is the main leading cause of chronic kidney disease worldwide. Although remarkable therapeutic advances have been made during the last few years, there still exists a high residual risk of disease progression to end-stage renal failure. To further understand the pathogenesis of tissue injury in this disease, by means of the Next-Generation Sequencing, we have studied the microRNA (miRNA) differential expression pattern in kidneys of Black and Tan Brachyury (BTBR) ob/ob (leptin deficiency mutation) mouse. This experimental model of type 2 diabetes and obesity recapitulates the key histopathological features described in advanced human DN and therefore can provide potential useful translational information. The miRNA-seq analysis, performed in the renal cortex of 22-week-old BTBR ob/ob mice, pointed out a set of 99 miRNAs significantly increased compared to non-diabetic, non-obese control mice of the same age, whereas no miRNAs were significantly decreased. Among them, miR-802, miR-34a, miR-132, miR-101a, and mir-379 were the most upregulated ones in diabetic kidneys. The in silico prediction of potential targets for the 99 miRNAs highlighted inflammatory and immune processes, as the most relevant pathways, emphasizing the importance of inflammation in the pathogenesis of kidney damage associated to diabetes. Other identified top canonical pathways were adipogenesis (related with ectopic fatty accumulation), necroptosis (an inflammatory and regulated form of cell death), and epithelial-to-mesenchymal transition, the latter supporting the importance of tubular cell phenotype changes in the pathogenesis of DN. These findings could facilitate a better understanding of this complex disease and potentially open new avenues for the design of novel therapeutic approaches to DN.

Rola autoimmunizacji w rozwoju powikłań cukrzycowych – przegląd badań

Przewlekłe powikłania cukrzycy są główną przyczyną obniżenia jakości życia, niepełnosprawności, a nawet przedwczesnej śmierci pacjentów cierpiących na tę chorobę. Mimo istotnego postępu w dziedzinie farmakoterapii, ich leczenie pozostaje nadal wyzwaniem w codziennej praktyce klinicznej. Brak terapii przyczynowej wynika z niewystarczającego zrozumienia molekularnych mechanizmów uszkadzających poszczególne narządy w cukrzycy. Uważa się, że etiopatogeneza tych powikłań jest złożona i zależy od czynników genetycznych i środowiskowych. W ich rozwoju, oprócz zaburzeń metabolicznych związanych z hiperglikemią, nasilenia stresu oksydacyjnego, dysfunkcji śródbłonka, indukcji stanu zapalnego, coraz częściej wskazuje się też na znaczącą rolę zaburzeń immunologicznych.

Wyniki badań doświadczalnych przeprowadzonych na zwierzętach, jak również na hodowlach tkankowych, oraz obserwacje kliniczne potwierdzają udział układu odpornościowego obejmujący aktywność autoreaktywnych limfocytów oraz cytotoksyczne działanie autoprzeciwciał w rozwoju poszczególnych powikłań w obu typach cukrzycy. Wydaje się zatem, że zachwianie równowagi immunologicznej wyzwalające autoagresję jest ważnym czynnikiem przyczyniającym się do dysfunkcji poszczególnych organów w typach cukrzycy 1 i 2.

Dokładne zrozumienie immunopatogenezy tych zaburzeń może zmienić dotychczasowe podejście w leczeniu powikłań cukrzycy oraz umożliwić opracowanie skutecznej terapii przyczynowej ukierunkowanej na układ odpornościowy. Identyfikacja swoistych autoprzeciwciał mogłaby usprawnić ich wczesną diagnostykę i prewencję. W artykule podjęto próbę analizy czynników ryzyka najczęstszych schorzeń o podłożu autoimmunizacyjnym, ich związku z typem 1 i 2 cukrzycy oraz podsumowano potencjalne znaczenie autoagresji w rozwoju jej powikłań w oparciu o wyniki dotychczasowych badań doświadczalnych i klinicznych.

Targeting Inflammatory Cytokines to Improve Type 2 Diabetes Control

Type 2 diabetes (T2D) is one of the most common chronic metabolic disorders in adulthood worldwide, whose pathophysiology includes an abnormal immune response accompanied by cytokine dysregulation and inflammation. As the T2D-related inflammation and its progression were associated with the balance between pro and anti-inflammatory cytokines, anticytokine treatments might represent an additional therapeutic option for T2D patients. This review focuses on existing evidence for antihyperglycemic properties of disease-modifying antirheumatic drugs (DMARDs) and anticytokine agents (anti-TNF-α, anti-interleukin-(IL-) 6, -IL-1, -IL-17, -IL-23, etc.). Emphasis is placed on their molecular mechanisms and on the biological rationale for clinical use. Finally, we briefly summarize the results from experimental model studies and promising clinical trials about the potential of anticytokine therapies in T2D, discussing the effects of these drugs on systemic and islet inflammation, beta-cell function, insulin secretion, and insulin sensitivity.

Identifying molecular insight of synergistic complexities for SARS-CoV-2 infection with pre-existing type 2 diabetes

The ongoing COVID-19 outbreak, caused by SARS-CoV-2, has posed a massive threat to global public health, especially to people with underlying health conditions. Type 2 diabetes (T2D) is lethal comorbidity of COVID-19. However, its pathogenetic link remains unclear. This research aims to determine the genetic factors and processes contributing to the synergistic severity of SARS-CoV-2 infection among T2D patients through bioinformatics approaches. We analyzed two sets of transcriptomic data of SARS-CoV-2 infection obtained from lung epithelium cells and PBMCs, and two sets of T2D data from pancreatic islet cells and PBMCs to identify the associated differentially expressed genes (DEGs) followed by their functional enrichment analyses in terms of protein-protein interaction (PPI) to detect hub-proteins and associated comorbidities, transcription factors (TFs), microRNAs (miRNAs) as well as the potential drug candidates. In PPI analysis, four potential hub-proteins (i.e., BIRC3, C3, MME, and IL1B) were identified among 25 DEGs shared between the disease pair. Enrichment analyses using the mutually overlapped DEGs revealed the most prevalent GO and cell signalling pathways, including TNF signalling, cytokine-cytokine receptor interaction, and IL-17 signalling, which are related to cytokine activities. Furthermore, as significant TFs, we identified IRF1, KLF11, FOSL1, and CREB3L1 while miRNAs including miR-1-3p, 34a-5p, 16–5p, 155–5p, 20a-5p, and let-7b-5p were found to be noteworthy. The findings illustrated the significant association between COVID-19 and T2D at the molecular level. These genetic determinants can further be explored for their specific roles in disease progression and therapeutic intervention, while significant pathways can also be studied as molecular checkpoints. Finally, the identified drug candidates may be evaluated for their potency to minimize the severity of COVID-19 patients with pre-existing T2D.

Renin-angiotensin system and inflammation update

The most classical view of the renin-angiotensin system (RAS) emphasizes its role as an endocrine regulator of sodium balance and blood pressure. However, it has long become clear that the RAS has pleiotropic actions that contribute to organ damage, including modulation of inflammation. Angiotensin II (Ang II) activates angiotensin type 1 receptors (AT1R) to promote an inflammatory response and organ damage. This represents the pathophysiological basis for the successful use of RAS blockers to prevent and treat kidney and heart disease. However, other RAS components could have a built-in capacity to brake proinflammatory responses. Angiotensin type 2 receptor (AT2R) activation can oppose AT1R actions, such as vasodilatation, but its involvement in modulation of inflammation has not been conclusively proven. Angiotensin-converting enzyme 2 (ACE2) can process Ang II to generate angiotensin-(1-7) (Ang-(1-7)), that activates the Mas receptor to exert predominantly anti-inflammatory responses depending on the context. We now review recent advances in the understanding of the interaction of the RAS with inflammation. Specific topics in which novel information became available recently include intracellular angiotensin receptors; AT1R posttranslational modifications by tissue transglutaminase (TG2) and anti-AT1R autoimmunity; RAS modulation of lymphoid vessels and T lymphocyte responses, especially of Th17 and Treg responses; interactions with toll-like receptors (TLRs), programmed necrosis, and regulation of epigenetic modulators (e.g. microRNAs and bromodomain and extraterminal domain (BET) proteins). We additionally discuss an often overlooked effect of the RAS on inflammation which is the downregulation of anti-inflammatory factors such as klotho, peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α), transient receptor potential ankyrin 1 (TRPA1), SNF-related serine/threonine-protein kinase (SNRK), serine/threonine-protein phosphatase 6 catalytic subunit (Ppp6C) and n-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP). Both transcription factors, such as nuclear factor κB (NF-κB), and epigenetic regulators, such as miRNAs are involved in downmodulation of anti-inflammatory responses. A detailed analysis of pathways and targets for downmodulation of anti-inflammatory responses constitutes a novel frontier in RAS research.

Ixekizumab May Improve Renal Function in Psoriasis

Background: Psoriasis is a chronic dermatological condition characterized by lesions on extensor surfaces, hands, feet, and genital areas. Chronic renal failure is often associated with metabolic syndrome and inflammatory conditions, such as psoriasis. Case report: In this paper, we report a patient with stage-three chronic renal failure that improved his renal condition after treatment with ixekizumab, an anti-IL17A drug used in the treatment of various cutaneous and rheumatological conditions. Conclusions: IL17A blockage may help to treat various autoimmune and inflammatory conditions, such as psoriasis, that may lead to renal impairment. Further investigation is necessary in order to prove the effectiveness of this drug in renal conditions.

Interleukin-17A: Potential mediator and therapeutic target in hypertension

Interleukin-17A (IL-17A) is a proinflammatory cytokine produced by cells of the immune system, predominantly Th17 and γδ lymphocytes. In this paper, we review the role of IL-17A in the pathogenesis of hypertension and in target organ damage. Preclinical studies in mice have shown that systemic adminstration of IL-17A increases blood pressure, probably by acting on multiple levels. Furthermore, IL-17A plasma concentrations are already elevated in patients with mild or moderate hypertension. Many studies in hypertensive mice models have detected IL-17A-producing cells in target organs such as the heart, vessels and kidneys. Patients with hypertensive nephrosclerosis show kidney infiltration by Th17 lymphocytes and γδ lymphocytes that express IL-17A. In addition, in experimental models of hypertension, the blockade of IL-17A by genetic strategies or using neutralizing antibodies, disminished blood pressure, probablyby acting on the small mesenteric arteries as well as in the regulation of tubule sodium transport. Moreover, IL-17A inhibition reduces end-organs damage. As a whole, the data presented in this review suggest that IL-17A participates in the regulation of blood pressure and in the genesis and maintenance of arterial hypertension, and may constitute a therapeutic target of hypertension-related pathologies in the future.

[Interleukin-17A: Possible mediator and therapeutic target in hypertension]

Interleukin-17A (IL-17A) is a proinflammatory cytokine produced by cells of the immune system, predominantly Th17 lymphocytes and γδ lymphocytes. In this paper, we review the role of IL-17A in the pathogenesis of hypertension and target organ damage. Studies in mice have shown that IL-17A increases blood pressure, probably by acting on multiple levels. Furthermore, IL-17A plasma concentrations are already elevated in patients with mild or moderate hypertension. Preclinical studies on arterial hypertension have detected IL-17A-producing cells in target organs such as the heart, vessels and kidneys. Patients with hypertensive nephrosclerosis show kidney infiltration by Th17 lymphocytes and γδ lymphocytes that express IL-17A. In addition, in experimental models of hypertension, blocking IL-17A by genetic strategies, or using neutralising antibodies, lowers blood pressure by acting on the vascular wall and tubule sodium transport and reduces damage to target organs. As a whole, the data presented in this review suggest that IL-17A participates in the regulation of blood pressure and in the genesis and maintenance of arterial hypertension, and may constitute a therapeutic target in the future.

T helper 17 cells in the pathophysiology of acute and chronic kidney disease

Both acute and chronic kidney disease have a strong underlying inflammatory component. This review focuses primarily on T helper 17 (Th17) cells as mediators of inflammation and their potential to modulate acute and chronic kidney disease. We provide updated information on factors and signaling pathways that promote Th17 cell differentiation with specific reference to kidney disease. We highlight numerous clinical studies that have investigated Th17 cells in the setting of human kidney disease and provide updated summaries from various experimental animal models of kidney disease indicating an important role for Th17 cells in renal fibrosis and hypertension. We focus on the pleiotropic effects of Th17 cells in different renal cell types as potentially relevant to the pathogenesis of kidney disease. Finally, we highlight studies that present contrasting roles for Th17 cells in kidney disease progression.

Contribution of Th17 cells to tissue injury in hypertension

PURPOSE OF REVIEW

Hypertension has been demonstrated to be a chief contributor to morbidity and mortality throughout the world. Although the cause of hypertension is multifactorial, emerging evidence, obtained in experimental studies, as well as observational studies in humans, points to the role of inflammation and immunity. Many aspects of immune function have now been implicated in hypertension and end-organ injury; this review will focus upon the recently-described role of Th17 cells in this pathophysiological response.

RECENT FINDINGS

Studies in animal models and human genetic studies point to a role in the adaptive immune system as playing a contributory role in hypertension and renal tissue damage. Th17 cells, which produce the cytokine IL17, are strongly pro-inflammatory cells, which may contribute to tissue damage if expressed in chronic disease conditions. The activity of these cells may be enhanced by physiological factors associated with hypertension such as dietary salt or Ang II. This activity may culminate in the increased sodium retaining activity and exacerbation of inflammation and renal fibrosis via multiple cellular mechanisms.

SUMMARY

Th17 cells are a distinct component of the adaptive immune system that may strongly enhance pathways leading to increased sodium reabsorption, elevated vascular tone and end-organ damage. Moreover, this pathway may lend itself towards specific targeting for treatment of kidney disease and hypertension.

Inflammatory Cytokines in Diabetic Kidney Disease: Pathophysiologic and Therapeutic Implications

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease and a main contributing factor for cardiovascular morbidity and mortality in patients with diabetes mellitus. Strategies employed to delay the progression of this pathology focus on the control of traditional risk factors, such as hyperglycemia, and elevated blood pressure. Although the intimate mechanisms involved in the onset and progression of DKD remain incompletely understood, inflammation is currently recognized as one of the main underlying processes. Untangling the mechanisms involved in the appearing of a harmful inflammatory response in the diabetic patient is crucial for the development of new therapeutic strategies. In this review, we focus on the inflammation-related pathogenic mechanisms involved in DKD and in the therapeutic utility of new anti-inflammatory strategies.

Associations of myeloperoxidase, interleukin-17A and heparin-binding EGF-like growth factor levels with in-stent restenosis after percutaneous coronary intervention: a single-centre case-control study in China

OBJECTIVES

To investigate the changes in serum myeloperoxidase (MPO), interleukin (IL)-17A and heparin-binding EGF-like growth factor (HB-EGF) levels before and after percutaneous coronary intervention (PCI), and to evaluate the associations of MPO, IL-17A and HB-EGF levels with the 1-year restenosis rate.

DESIGN

Case-control study.

SETTINGS

Xiangyang Central Hospital between January 2012 and December 2017.

PARTICIPANTS

Patients with coronary heart disease who underwent PCI.

INTERVENTIONS

Not applicable.

PRIMARY AND SECONDARY OUTCOME MEASURES

Not applicable.

RESULTS

Finally, 407 and 132 patients were included in the control and in-stent restenosis (ISR) groups, respectively. The general clinical characteristics of the patients were not significantly different between the two groups. The MPO, IL-17A and HB-EGF levels were not significantly different between the two groups at baseline but significantly increased after PCI. The ISR group showed higher levels of MPO, IL-17A and HB-EGF compared with the control group at all postoperative time points. Multivariable analysis showed that MPO, IL-17A and HB-EGF were associated with increased ISR [MPO (OR=1.003; 95% CI: 1.001 to 1.005; p=0.002), IL-17A (OR=1.015; 95% CI: 1.009 to 1.020; p<0.0001) and HB-EGF (OR=2.256; 95% CI: 1.103 to 4.009; p=0.002)]. All three factors had sensitivity and specificity ≥68% for ISR.

CONCLUSIONS

HB-EGF could be used for the detection of ISR after PCI and could be of use for the prediction of ISR, but the value of MPO and IL-17A might be more limited. This will have to be validated in future studies.

IL-17A as a Potential Therapeutic Target for Patients on Peritoneal Dialysis

Chronic kidney disease (CKD) is a health problem reaching epidemic proportions. There is no cure for CKD, and patients may progress to end-stage renal disease (ESRD). Peritoneal dialysis (PD) is a current replacement therapy option for ESRD patients until renal transplantation can be achieved. One important problem in long-term PD patients is peritoneal membrane failure. The mechanisms involved in peritoneal damage include activation of the inflammatory and immune responses, associated with submesothelial immune infiltrates, angiogenesis, loss of the mesothelial layer due to cell death and mesothelial to mesenchymal transition, and collagen accumulation in the submesothelial compact zone. These processes lead to fibrosis and loss of peritoneal membrane function. Peritoneal inflammation and membrane failure are strongly associated with additional problems in PD patients, mainly with a very high risk of cardiovascular disease. Among the inflammatory mediators involved in peritoneal damage, cytokine IL-17A has recently been proposed as a potential therapeutic target for chronic inflammatory diseases, including CKD. Although IL-17A is the hallmark cytokine of Th17 immune cells, many other cells can also produce or secrete IL-17A. In the peritoneum of PD patients, IL-17A-secreting cells comprise Th17 cells, γδ T cells, mast cells, and neutrophils. Experimental studies demonstrated that IL-17A blockade ameliorated peritoneal damage caused by exposure to PD fluids. This article provides a comprehensive review of recent advances on the role of IL-17A in peritoneal membrane injury during PD and other PD-associated complications.

Epigenetic Modifiers as Potential Therapeutic Targets in Diabetic Kidney Disease

Diabetic kidney disease is one of the fastest growing causes of death worldwide. Epigenetic regulators control gene expression and are potential therapeutic targets. There is functional interventional evidence for a role of DNA methylation and the histone post-translational modifications-histone methylation, acetylation and crotonylation-in the pathogenesis of kidney disease, including diabetic kidney disease. Readers of epigenetic marks, such as bromodomain and extra terminal (BET) proteins, are also therapeutic targets. Thus, the BD2 selective BET inhibitor apabetalone was the first epigenetic regulator to undergo phase-3 clinical trials in diabetic kidney disease with an endpoint of kidney function. The direct therapeutic modulation of epigenetic features is possible through pharmacological modulators of the specific enzymes involved and through the therapeutic use of the required substrates. Of further interest is the characterization of potential indirect effects of nephroprotective drugs on epigenetic regulation. Thus, SGLT2 inhibitors increase the circulating and tissue levels of β-hydroxybutyrate, a molecule that generates a specific histone modification, β-hydroxybutyrylation, which has been associated with the beneficial health effects of fasting. To what extent this impact on epigenetic regulation may underlie or contribute to the so-far unclear molecular mechanisms of cardio- and nephroprotection offered by SGLT2 inhibitors merits further in-depth studies.

Special Issue "Diabetic Nephropathy: Diagnosis, Prevention and Treatment"

Diabetic nephropathy (DN) is the main cause of end-stage renal disease. DN is a complex disease mediated by genetic and environmental factors, and many cellular and molecular mechanisms are involved in renal damage in diabetes. There are no biomarkers that reflect the severity of the underlying renal histopathological changes and can effectively predict the progression of renal damage and stratify the risk of DN among individuals with diabetes mellitus. Current therapeutic strategies are based on the strict control of glucose and blood pressure levels and, although there are new anti-diabetic drugs, these treatments only retard renal damage progression, being necessary novel therapies. In this Special Issue, there are several comprehensive reviews and interesting original papers covering all these topics, which would be of interest to the growing number of readers of the Journal of Clinical Medicine.

lncRNA MEG8 Upregulates miR-770-5p Through Methylation and Promotes Cell Apoptosis in Diabetic Nephropathy

BACKGROUND

It has been reported that lncRNA MEG8 can be induced by glucose in mice model of kidney injury, indicating its role in diabetic nephropathy (DN). This study was carried out to explore the role of MEG8 in DN.

MATERIALS AND METHODS

The expression of MEG8 and miR-770-5p in plasma samples from DN patients (n = 66), diabetic patients (DM patients with no complications, n = 66) and healthy controls (n = 66) was detected by RT-qPCR. The interaction between MEG8 and miR-770-5p in podocyte cells was evaluated by transient transfections. Cell apoptosis under high-glucose treatment was detected by cell apoptosis assay.

RESULTS

MEG8 and miR-770-5p were upregulated in plasma of DM patients and were further upregulated in DN patients. MEG8 was positively correlated with miR-770-5p. In podocyte cells, high-glucose treatment resulted in increased expression levels of MEG8 and miR-770-5p. In podocyte cells, overexpression of MEG8 resulted in upregulated expression of miR-770-5p and decreased methylation of the miR-770-5p gene. Cell apoptosis analysis showed that overexpression of MEG8 and miR-770-5p resulted in increased cell apoptotic rate under glucose treatment. In addition, combined overexpression of MEG8 and miR-770-5p showed stronger effects.

CONCLUSION

MEG8 may upregulate miR-770-5p through methylation to promote DN by promoting cell apoptosis.