Therapeutic effects of interleukin-1 receptor-associated kinase 4 inhibitor AS2444697 on diabetic nephropathy in type 2 diabetic mice

Upregulation of Piezo2 and increased extracellular matrix protein in diabetic kidney disease mice

Mechanical forces such as glomerular hyperfiltration are crucial in the pathogenesis and progression of diabetic kidney disease. Piezo2 is a mechanosensitive cation channel and plays a major role in various biological and pathophysiological phenomena. We previously reported Piezo2 expression in mouse and rat kidneys and its alteration by dehydration and hypertension. To elucidate the alteration of Piezo2 expression and its consequences in a mouse model of diabetic kidney disease, we used high salt-fed male KK-Ay mice, an accelerated genetic model of diabetic kidney disease. KK-Ay mice exhibited marked obesity, hyperglycemia, elevated blood pressure, higher creatinine clearance, and overt albuminuria. Histopathological analysis revealed glomerular hypertrophy, mesangial expansion, macrophage infiltration, tubular vacuolization, and interstitial fibrosis. The mRNA and protein expression analyses revealed (1) increased fibronectin protein expression in the glomerular areas, (2) upregulated Piezo2 expression in the glomerular mesangial cells and interstitial region, (3) increased Piezo2 and the fibronectin-coding gene Fn1 mRNA, and (4) a strong correlation of Piezo2 expression with that of Fn1 in the kidneys of diabetic kidney disease mice. Piezo2 upregulation and fibronectin accumulation were alleviated by an angiotensin II receptor blocker. In accordance with these in vivo results, in vitro study demonstrated that Piezo2 overexpression increased fibronectin production in HEK293T cells. In conclusion, we demonstrated that Piezo2 expression was upregulated in glomerular mesangial cells in a mouse model of diabetic kidney disease. Our results suggest that Piezo2 contributes to the progression of diabetic kidney disease by mediating glomerular fibronectin production, leading to glomerulosclerosis. Hyperfiltration is crucial in the pathogenesis of diabetic kidney disease. We showed that Piezo2 expression is upregulated in mesangial cells of diabetic kidney disease mice with glomerular fibronectin accumulation. Piezo2 overexpression increased fibronectin production in HEK293T cells. Piezo2 may contribute to diabetic kidney disease progression by mediating glomerular fibronectin production.

Swollen Feet: Considering the Paradoxical Roles of Interleukins in Nephrotic Syndrome

Interleukins are a family of 40 bioactive peptides that act through cell surface receptors to induce a variety of intracellular responses. While interleukins are most commonly associated with destructive, pro-inflammatory signaling in cells, some also play a role in promoting cellular resilience and survival. This review will highlight recent evidence of the cytoprotective actions of the interleukin 1 receptor (IL-1R)- and common gamma chain receptor (IL-Rγc)-signaling cytokines in nephrotic syndrome (NS). NS results from the injury or loss of glomerular visceral epithelial cells (i.e., podocytes). Although the causes of podocyte dysfunction vary, it is clear that pro-inflammatory cytokines play a significant role in regulating the propagation, duration and severity of disease. Pro-inflammatory cytokines signaling through IL-1R and IL-Rγc have been shown to exert anti-apoptotic effects in podocytes through the phosphoinositol-3-kinase (PI-3K)/AKT pathway, highlighting the potential utility of IL-1R- and IL-Rγc-signaling interleukins for the treatment of podocytopathy in NS. The paradoxical role of interleukins as drivers and mitigators of podocyte injury is complex and ill-defined. Emerging evidence of the cytoprotective role of some interleukins in NS highlights the urgent need for a nuanced understanding of their pro-survival benefits and reveals their potential as podocyte-sparing therapeutics for NS.

Emerging trends in IRAK-4 kinase research

The IRAK-4 kinase lies at a critical signaling node that drives cancer cell survival through multiple mechanisms, activation, and translocation of NF-κB mediated inflammatory responses and innate immune signaling through regulation of interferon-α/β receptor (IFNα/β). Inhibition, of IRAK-4, has consequently drawn a lot of attention in recent years to address indications ranging from oncology to autoimmune disorders to neurodegeneration, etc. However, the key stumbling block in targeting IRAK-4 is that despite the inhibition of the kinase activity using an inhibitor the target remains effective, reducing the potential of an inhibitor. This is due to the "scaffolding effect" because of which although regulation of downstream processes by IRAK-4 has been primarily linked with kinase function; however, still, various reports have suggested that IRAK-4 has a non-kinase function in a variety of cell types. This is attributed to the myddosome complex formed by IRAK-4 with myd88, IRAK-2, and IRAK-1 which by itself can cause the activation of downstream effector TRAF6 despite inhibition of the kinase domain of IRAK-4. With this challenge, several groups initiated the development of targeting protein degraders of IRAK-4 using Proteolysis-Targeting Chimeras (PROTACs) technology to completely remove the IRAK-4 from the cellular milieu. In this review, we will capture all these developments and the evolving science around this target.

The recent advance of Interleukin-1 receptor associated kinase 4 inhibitors for the treatment of inflammation and related diseases

The interleukin-1 receptor associated kinase 4 (IRAK-4) is a member of serine-threonine kinase family, which plays an important role in the regulation of interleukin-1 receptors (IL-1R) and Toll-like receptors (TLRs) related signaling pathways. At present, the IRAK-4 mediated inflammation and related signaling pathways contribute to inflammation, which are also responsible for other autoimmune diseases and drug resistance in cancers. Therefore, targeting IRAK-4 to develop single-target, multi-target inhibitors and proteolysis-targeting chimera (PROTAC) degraders is an important direction for the treatment of inflammation and related diseases. Moreover, insight into the mechanism of action and structural optimization of the reported IRAK-4 inhibitors will provide the new direction to enrich the clinical therapies for inflammation and related diseases. In this comprehensive review, we introduced the recent advance of IRAK-4 inhibitors and degraders with regards to structural optimization, mechanism of action and clinical application that would be helpful for the development of more potent chemical entities against IRAK-4.

Design, synthesis, and pharmacological evaluation of N-(3-carbamoyl-1H-pyrazol-4-yl)-1,3-oxazole-4-carboxamide derivatives as interleukin-1 receptor-associated kinase 4 inhibitors with reduced potential for cytochrome P450 1A2 induction

Interleukin-1 receptor-associated kinase 4 (IRAK4) is a critical molecule in Toll-like receptor/interleukin-1 receptor signaling and an attractive therapeutic target for a wide range of inflammatory and autoimmune diseases as well as cancers. In our search for novel IRAK4 inhibitors, we conducted structural modification of a thiazolecarboxamide derivative 1, a lead compound derived from high-throughput screening hits, to elucidate structure-activity relationship and improve drug metabolism and pharmacokinetic (DMPK) properties. First, conversion of the thiazole ring of 1 to an oxazole ring along with introduction of a methyl group at the 2-position of the pyridine ring aimed at reducing cytochrome P450 (CYP) inhibition were conducted to afford 16. Next, modification of the alkyl substituent at the 1-position of the pyrazole ring of 16 aimed at improving CYP1A2 induction properties revealed that branched alkyl and analogous substituents such as isobutyl (18) and (oxolan-3-yl)methyl (21), as well as six-membered saturated heterocyclic groups such as oxan-4-yl (2), piperidin-4-yl (24, 25), and dioxothian-4-y (26), are effective for reducing induction potential. Representative compound AS2444697 (2) exhibited potent IRAK4 inhibitory activity with an IC50 value of 20 nM and favorable DMPK properties such as low risk of drug-drug interactions mediated by CYPs as well as excellent metabolic stability and oral bioavailability.

The Influence of Different Types of Diabetes on Vascular Complications

The final outcome of diabetes is chronic complications, of which vascular complications are the most serious, which is the main cause of death for diabetic patients and the direct cause of the increase in the cost of diabetes. Type 1 and type 2 diabetes are the main types of diabetes, and their pathogenesis is completely different. Type 1 diabetes is caused by genetics and immunity to destroy a large number of β cells, and insulin secretion is absolutely insufficient, which is more prone to microvascular complications. Type 2 diabetes is dominated by insulin resistance, leading to atherosclerosis, which is more likely to progress to macrovascular complications. This article explores the pathogenesis of two types of diabetes, analyzes the pathogenesis of different vascular complications, and tries to explain the different trends in the progression of different types of diabetes to vascular complications, in order to better prevent diabetes and its vascular complications.

Potential associations between variants of genes encoding regulators of inflammation, and mediators of inflammation in type 2 diabetes and insulin resistance

WHAT IS KNOWN AND OBJECTIVE

Type 2 diabetes (T2DM) is a multigenic disease that develops with impaired β-cell function and insulin sensitivity and has a high prevalence worldwide. A cause often postulated for type 2 diabetes is chronic inflammation. It has been suggested that inflammatory regulators can inhibit insulin signal transduction and that inflammation is involved in insulin resistance (IR) and the pathogenesis of type 2 diabetes. In this direction, we aimed to investigate the gene variants of MyD88 (rs1319438, rs199396), IRAK4 (rs1461567, rs4251513, rs4251559) and TRAF6 (rs331455, rs331457) and serum levels of COX-2, NF-κB, iNOS in T2DM and IR.

METHODS

The MyD88, IRAK4 and TRAF6 variations were genotyped in 100 newly diagnosed T2DM patients and 100 non-diabetic individuals using The MassARRAY® Iplex GOLD SNP genotyping method. The COX-2, iNOS and NF-κB levels were measured in serum samples with the sandwich-ELISA method. Results were analysed using SPSS Statistics software and the online FINNETI program.

RESULTS AND DISCUSSION

In our study, a total of the 7 variants in the MyD88, IRAK4 and TRAF6 genes were genotyped, and as a result, no relationship was found between most of these variants and the risk of type 2 diabetes and insulin resistance (p > 0.05). Only, the rs1461567 variant of the IRAK4 gene was significant in the heterozygous model (CC vs. CT), and the CT genotype was most frequent in diabetic individuals compared with the non-diabetics (p = 0.033). Additionally, COX-2 and iNOS levels were found to be associated with diabetes and insulin resistance (p < 0.05).

WHAT IS NEW AND CONCLUSION

Our results show that high COX-2 and iNOS levels are associated with T2DM, besides MyD88, IRAK4 and TRAF6 gene variations may not be closely related to type 2 diabetes and insulin resistance. Nevertheless, studies in this pathway with a different population and a large number of patients are important.

Mefunidone ameliorates diabetic kidney disease in STZ and db/db mice

Diabetic kidney disease (DKD) is a major cause of end stage renal diseases worldwide. Despite successive interventions for delaying the progression of DKD, current treatments cannot reverse the pathological progression. Mefunidone (MFD) is a new compound with potent antifibrotic properties, but the effect of MFD on DKD remains unknown. Therefore, we investigated the protective effects of MFD in both models of the db/db type 2 diabetes (T2D) and streptozotocin (STZ)-induced type 1 diabetes (T1D) models. Compared with the model group, MFD treatment significantly reduced pathological changes observed by PAS staining, PASM staining, and Masson staining in vivo. To further elucidate the potential mechanisms, we discovered MFD treatment notably restored podocyte function, alleviated inflammation, abated ROS generation, inhibited the TGF-β1/SAMD2/3 pathway, suppressed the phosphorylation levels of MAPKs (ERK1/2, JNK, and P38), and reduced epithelial-to-mesenchymal transition(EMT). In conclusion, these findings demonstrate the effectiveness of MFD in diabetic nephropathy and elucidate its possible mechanism.

Integrated analysis of circRNA-miRNA-mRNA regulatory network identifies potential diagnostic biomarkers in diabetic foot ulcer

Diabetic foot ulcer (DFU) is a common and serious complication of diabetes mellitus, which influences patients’ quality of life. Recently, circRNA regulated the mRNA levels by functioning as miRNA sponge in various disease, including diabetes mellitus. Nevertheless, the circRNA-miRNA-mRNA regulatory network involved in DFU remains obscure. The aim of this study is to construct a competing endogenous RNA (ceRNA) network and screen biological indicators as diagnostic factors in DFU.

All the differentially expressed circRNAs, miRNAs and mRNAs were derived from Gene Expression Omnibus database. Furthermore, circRNAs identified by cytoHubba analysis and miRNAs obtained by human miRNA-disease database were used to construct DFU-specific ceRNA network with intersection of mRNAs. Functional enrichment analysis displayed the function and pathway of dysregulated mRNAs. Hub genes with high diagnostic value were screened by ClusterONE, GO semantic similarity and receiver operating characteristic (ROC) curve.

Here, the ceRNA network consisted of 8 circRNAs, 11 miRNAs and 91 mRNAs. Functional enrichment analysis demonstrated diabetic complications-related pathway including TGF-beta, FoxO and Wnt signaling pathway. GO semantic similarity and ROC curve analysis showed 6 hub genes with high diagnostic value (the area under the ROC curve ≥ 0.8) in patients with DFU, including BCL2, CCND1, IRAK4, SMAD4, SP1 and SUFU, which were identified as potential target genes for DFU diagnosis. In conclusion, the present study looked at a circRNA-miRNA-mRNA regulatory network with DFU and screened the potential function of mRNA, then identified novel diagnostic biomarkers and therapeutic targets for patients with DFU.