Novel avenues for drug discovery in diabetic kidney disease

Dysregulation of neutrophil extracellular traps (NETs)-related genes in the pathogenesis of diabetic kidney disease - Results from bioinformatics analysis and translational studies

The role of Neutrophil extracellular traps (NETs) in the immunopathogenesis of Diabetic Kidney Disease (DKD) remains elusive. We used a machine learning approach to identify differentially expressed genes (DEGs) associated with NETs in human DKD kidney biopsy datasets and validated the results using single-nucleus RNA sequencing datasets. The expressions of these candidate genes and related cytokines were verified in blood obtained from DKD patients. Three NETs-associated genes (ITGAM, ITGB2 and TLR7) were identified, which all showed significant upregulation in both glomerular and tubulointerstitial compartments in human DKD kidneys. DKD patients showed significantly higher number of activated neutrophils with increased ITGAM and ITGB2 expression, higher serum IL-6 but lower IL-10, compared to healthy controls (p all <0.01). This study suggests that dysregulation of NETs-associated genes ITGAM and ITGB2 are related to the pathogenesis of DKD, and may serve as novel diagnostic markers and therapeutic targets in DKD.

Discovery of new anti-diabetic potential agents based on paracetamol incorporating sulfa-drugs: Design, synthesis, α-amylase, and α-glucosidase inhibitors with molecular docking simulation

Uncontrolled diabetes can lead to hyperglycemia, which causes neuropathy, heart attacks, retinopathy, and nervous system damage over time, therefore, controlling hyperglycemia using potential drug target inhibitors is a promising strategy. This work focused on synthesizing new derivatives via the diazo group, using a hybridization strategy involving two approved drugs, paracetamol and several sulfonamides. The newly designed diazo-paracetamols 5-12 were fully characterized and then screened for in vitro α-amylase and α-glucosidase activities and exhibited inhibitory percentages (IP) = 92.5-96.5 % and 91.0-95.7 % compared to Acarbose IP = 96.5 and 95.8 %, respectively at 100 μg/mL. The IC50 values of the synthesized derivatives were evaluated against α-amylase and α-glucosidase enzymes, and the results demonstrated moderate to potent activity. Among the tested diazo-paracetamols, compound 11 was found to have the highest potency activity against α-amylase with IC50 value of 0.98 ± 0.015 μM compared to Acarbose IC50 = 0.43 ± 0.009 μM, followed by compound 10 (IC50 = 1.55 ± 0.022 μM) and compound 9 (IC50 = 1.59 ± 0.023 μM). On the other hand, for α-glucosidase, compound 10 with pyrimidine moiety demonstrated the highest inhibitory activity with IC50 = 1.39 ± 0.021 μM relative to Acarbose IC50 = 1.24 ± 0.029 μM and the order of the most active derivatives was 10 > 9 (IC50 = 2.95 ± 0.046 μM) > 11 (IC50 = 5.13 ± 0.082 μM). SAR analysis confirmed that the presence of 4,5-dimethyl-isoxazole or pyrimidine nucleus attached to the sulfonyl group is important for activity. Finally, the docking simulation was achieved to determine the mode of binding interactions for the most active derivatives in the enzyme's active site.

Causal relationship between gut microbiota and diabetic nephropathy: a two-sample Mendelian randomization study

Objective

Emerging evidence has provided compelling evidence linking gut microbiota (GM) and diabetic nephropathy (DN) via the "gut-kidney" axis. But the causal relationship between them hasn't been clarified yet. We perform a Two-Sample Mendelian randomization (MR) analysis to reveal the causal connection with GM and the development of DN, type 1 diabetes nephropathy (T1DN), type 2 diabetes nephropathy (T2DN), type 1 diabetes mellitus (T1DM), and type 2 diabetes mellitus (T2DM).

Methods

We used summary data from MiBioGen on 211 GM taxa in 18340 participants. Generalized MR analysis methods were conducted to estimate their causality on risk of DN, T1DN, T2DN, T1DM and T2DM from FinnGen. To ensure the reliability of the findings, a comprehensive set of sensitivity analyses were conducted to confirm the resilience and consistency of the results.

Results

It was showed that Class Verrucomicrobiae [odds ratio (OR) =1.5651, 95%CI:1.1810-2.0742,PFDR=0.0018], Order Verrucomicrobiales (OR=1.5651, 95%CI: 1.1810-2.0742, PFDR=0.0018) and Family Verrucomicrobiaceae (OR=1.3956, 95%CI:1.0336-1.8844, PFDR=0.0296) had significant risk of DN. Our analysis found significant associations between GM and T2DN, including Class Verrucomimicrobiae (OR=1.8227, 95% CI: 1.2414-2.6763, PFDR=0.0139), Order Verrucomimicrobiae (OR=1.5651, 95% CI: 1.8227-2.6764, PFDR=0.0024), Rhodospirillales (OR=1.8226, 95% CI: 1.2412-2.6763, PFDR=0.0026), and Family Verrucomicroniaceae (OR=1.8226, 95% CI: 1.2412-2.6763, PFDR=0.0083). The Eubacteriumprotogenes (OR=0.4076, 95% CI: 0.2415-0.6882, PFDR=0.0021) exhibited a protection against T1DN. Sensitivity analyses confirmed that there was no significant heterogeneity and pleiotropy.

Conclusions

At the gene prediction level, we identified the specific GM that is causally linked to DN in both T1DM and T2DM patients. Moreover, we identified distinct microbial changes in T1DN that differed from those seen in T2DN, offering valuable insights into GM signatures associated with subtype of nephropathy.

FCMSTrans: Accurate Prediction of Disease-Associated nsSNPs by Utilizing Multiscale Convolution and Deep Feature Combination within a Transformer Framework

Nonsynonymous single-nucleotide polymorphisms (nsSNPs), implicated in over 6000 diseases, necessitate accurate prediction for expedited drug discovery and improved disease diagnosis. In this study, we propose FCMSTrans, a novel nsSNP predictor that innovatively combines the transformer framework and multiscale modules for comprehensive feature extraction. The distinctive attribute of FCMSTrans resides in a deep feature combination strategy. This strategy amalgamates evolutionary-scale modeling (ESM) and ProtTrans (PT) features, providing an understanding of protein biochemical properties, and position-specific scoring matrix, secondary structure, predicted relative solvent accessibility, and predicted disorder (PSPP) features, which are derived from four protein sequences and structure-oriented characteristics. This feature combination offers a comprehensive view of the molecular dynamics involving nsSNPs. Our model employs the transformer's self-attention mechanisms across multiple layers, extracting higher-level and abstract representations. Simultaneously, varied-level features are captured by multiscale convolutions, enriching feature abstraction at multiple echelons. Our comparative analyses with existing methodologies highlight significant improvements made possible by the integrated feature fusion approach adopted in FCMSTrans. This is further substantiated by performance assessments based on diverse data sets, such as PredictSNP, MMP, and PMD, with areas under the curve (AUCs) of 0.869, 0.819, and 0.693, respectively. Furthermore, FCMSTrans shows robustness and superiority by outperforming the current best predictor, PROVEAN, in a blind test conducted on a third-party data set, achieving an impressive AUC score of 0.7838. The Python code of FCMSTrans is available at https://github.com/gc212/FCMSTrans for academic usage.

Synthesis and biological evaluation of 2'-hydroxychalcone derivatives as AMPK activators

A series of 2'-hydroxychalcone derivatives with various substituents on B-ring were synthesized and evaluated for AMP-activated protein kinase (AMPK) activation activity in podocyte cells. The results displayed that hydroxy, methoxy and methylenedioxy groups on B-ring could enhance the activitiy better than O-saturated alkyl, O-unsaturated alkyl or other alkoxy groups. Compounds 27 and 29 possess the highest fold change of 2.48 and 2.73, respectively, which were higher than those of reference compound (8) (1.28) and metformin (1.88). Compounds 27 and 29 were then subjected to a concentration-response study to obtain the EC50 values of 2.0 and 4.8 µM, respectively and MTT assays also showed that cell viability was not influenced by the exposure of podocytes to compounds 27 and 29 at concentrations up to 50 μM. In addition, compound 27 was proved to activate AMPK via calcium/calmodulin-dependent protein kinase kinase β (CaMKKβ)-dependent pathway without affecting intracellular calcium levels. The computational study showed that the potent compounds exhibited stronger ligand-binding strength to CaMKKβ, particularly compounds 27 (-8.4 kcal/mol) and 29 (-8.0 kcal/mol), compared to compound 8 (-7.5 kcal/mol). Fragment molecular orbital (FMO) calculation demonstrated that compound 27 was superior to compound 29 due to the presence of methyl group, which amplified the binding by hydrophobic interactions. Therefore, compound 27 would represent a promising AMPK activator for further investigation of the treatment of diabetes and diabetic nephropathy.

A sulfonamide chalcone AMPK activator ameliorates hyperglycemia and diabetic nephropathy in db/db mice

Diabetic nephropathy (DN) is a serious complication of diabetes mellitus (DM), which currently lacks effective treatments. AMP-activated protein kinase (AMPK) stimulation by chalcones, a class of polyphenols abundantly found in plants, is proposed as a promising therapeutic approach for DM. This study aimed to identify novel chalcone derivatives with improved AMPK-stimulating activity in human podocytes and evaluate their mechanisms of action as well as in vivo efficacy in a mouse model of DN. Among 133 chalcone derivatives tested, the sulfonamide chalcone derivative IP-004 was identified as the most potent AMPK activator in human podocytes. Western blot analyses, intracellular calcium measurements and molecular docking simulation indicated that IP-004 activated AMPK by mechanisms involving direct binding at allosteric site of calcium-dependent protein kinase kinase β (CaMKKβ) without affecting intracellular calcium levels. Interestingly, eight weeks of intraperitoneal administration of IP-004 (20 mg/kg/day) significantly decreased fasting blood glucose level, activated AMPK in the livers, muscles and glomeruli, and ameliorated albuminuria in db/db type II diabetic mice. Collectively, this study identifies a novel chalcone derivative capable of activating AMPK in vitro and in vivo and exhibiting efficacy against hyperglycemia and DN in mice. Further development of AMPK activators based on chalcone derivatives may provide an effective treatment of DN.

Fungus-Derived 3-Hydroxyterphenyllin and Candidusin A Ameliorate Palmitic Acid-Induced Human Podocyte Injury via Anti-Oxidative and Anti-Apoptotic Mechanisms

Diabetic nephropathy (DN) is a leading cause of end-stage renal disease. An elevated fatty acid plasma concentration leads to podocyte injury and DN progression. This study aimed to identify and characterize cellular mechanisms of natural compounds that inhibit palmitic acid (PA)-induced human podocyte injury. By screening 355 natural compounds using a cell viability assay, 3-hydroxyterphenyllin (3-HT) and candidusin A (CDA), isolated from the marine-derived fungus Aspergillus candidus PSU-AMF169, were found to protect against PA-induced podocyte injury, with half-maximal inhibitory concentrations (IC₅₀) of ~16 and ~18 µM, respectively. Flow cytometry revealed that 3-HT and CDA suppressed PA-induced podocyte apoptosis. Importantly, CDA significantly prevented PA-induced podocyte barrier impairment as determined by 70 kDa dextran flux. Reactive oxygen species (ROS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) direct scavenging assays indicated that both compounds exerted an anti-oxidative effect via direct free radical-scavenging activity. Moreover, 3-HT and CDA upregulated the anti-apoptotic Bcl2 protein. In conclusion, 3-HT and CDA represent fungus-derived bioactive compounds that have a novel protective effect on PA-induced human podocyte apoptosis via mechanisms involving free radical scavenging and Bcl2 upregulation.

FcER1: A Novel Molecule Implicated in the Progression of Human Diabetic Kidney Disease

Diabetic kidney disease (DKD) is a key microvascular complication of diabetes, with few therapies for targeting renal disease pathogenesis and progression. We performed transcriptional and protein studies on 103 unique blood and kidney tissue samples from patients with and without diabetes to understand the pathophysiology of DKD injury and its progression. The study was based on the use of 3 unique patient cohorts: peripheral blood mononuclear cell (PBMC) transcriptional studies were conducted on 30 patients with DKD with advancing kidney injury; Gene Expression Omnibus (GEO) data was downloaded, containing transcriptional measures from 51 microdissected glomerulous from patients with DKD. Additionally, 12 independent kidney tissue sections from patients with or without DKD were used for validation of target genes in diabetic kidney injury by kidney tissue immunohistochemistry and immunofluorescence. PBMC DKD transcriptional analysis, identified 853 genes (p < 0.05) with increasing expression with progression of albuminuria and kidney injury in patients with diabetes. GEO data was downloaded, normalized, and analyzed for significantly changed genes. Of the 325 significantly up regulated genes in DKD glomerulous (p < 0.05), 28 overlapped in PBMC and diabetic kidney, with perturbed FcER1 signaling as a significantly enriched canonical pathway. FcER1 was validated to be significantly increased in advanced DKD, where it was also seen to be specifically co-expressed in the kidney biopsy with tissue mast cells. In conclusion, we demonstrate how leveraging public and private human transcriptional datasets can discover and validate innate immunity and inflammation as key mechanistic pathways in DKD progression, and uncover FcER1 as a putative new DKD target for rational drug design.

Scientific Advances in Diabetes: The Impact of the Innovative Medicines Initiative

Diabetes Mellitus is one of the World Health Organization's priority diseases under research by the first and second programmes of Innovative Medicines Initiative, with the acronyms IMI1 and IMI2, respectively. Up to October of 2019, 13 projects were funded by IMI for Diabetes & Metabolic disorders, namely SUMMIT, IMIDIA, DIRECT, StemBANCC, EMIF, EBiSC, INNODIA, RHAPSODY, BEAT-DKD, LITMUS, Hypo-RESOLVE, IM2PACT, and CARDIATEAM. In general, a total of €447 249 438 was spent by IMI in the area of Diabetes. In order to prompt a better integration of achievements between the different projects, we perform a literature review and used three data sources, namely the official project's websites, the contact with the project's coordinators and co-coordinator, and the CORDIS database. From the 662 citations identified, 185 were included. The data collected were integrated into the objectives proposed for the four IMI2 program research axes: (1) target and biomarker identification, (2) innovative clinical trials paradigms, (3) innovative medicines, and (4) patient-tailored adherence programmes. The IMI funded projects identified new biomarkers, medical and research tools, determinants of inter-individual variability, relevant pathways, clinical trial designs, clinical endpoints, therapeutic targets and concepts, pharmacologic agents, large-scale production strategies, and patient-centered predictive models for diabetes and its complications. Taking into account the scientific data produced, we provided a joint vision with strategies for integrating personalized medicine into healthcare practice. The major limitations of this article were the large gap of data in the libraries on the official project websites and even the Cordis database was not complete and up to date.

Effects of Dexmedetomidine on the RhoA /ROCK/ Nox4 Signaling Pathway in Renal Fibrosis of Diabetic Rats

Objective

To investigate the effects and mechanisms of dexmedetomidine (Dex) on model rats of diabetic nephropathy (DN).

Methods

Rats were divided into NC, model, Dex-L (1μg/ kg), Dex-M (5μg/kg) and Dex-H (10μg/kg) groups. Rats in all groups except in the NC group were injected with streptozotocin (STZ) combined with right nephrectomy. Rats in Dex (1, 5 and 10μg/kg) groups received gavage with Dex (1, 5 and 10μg/kg). After 4 weeks, rats were sacrificed and kidneys were collected. HE staining was performed for a renal injury. Masson staining was applied to detect the fibrotic accumulation in rat kidney. Radioimmunoassay was used to test the renal function. Immunohistochemical method was used to detect protein expressions of RhoA, p-MYPT and Nox4 in rat kidney.

Results

Compared with the NC group, the levels of urine microalbumin in protein, α1-MG and β2-MG, renal fibrotic accumulation, RhoA, p-MYPT, Nox4 and α-SMA in model group increased significantly (P＜0.001, respectively). Compared with the model group, Dex low, medium and high groups improved the deposition of renal fiber in rats, inhibited the expression levels of microalbumin, α1-MG and β2-MG in urine and decreased expression of RhoA, p-MYPT, Nox4 and α-SMA proteins (P＜0.05, P＜0.01).

Conclusion

Dex is possible to inhibit the expression of α-SMA and renal fibrous substance deposition in rat kidney via RhoA/ROCK/Nox4 signaling pathway, thereby reducing early kidney damage in model rats.

Long noncoding RNA: an emerging player in diabetes and diabetic kidney disease

Diabetic kidney disease (DKD) is among the most common complications of diabetes mellitus (DM), and remains the leading cause of end-stage renal diseases (ESRDs) in developed countries, with no definitive therapy yet available. It is imperative to decipher the exact mechanisms underlying DKD and identify novel therapeutic targets. Burgeoning evidence indicates that long non-coding RNAs (lncRNAs) are essential for diverse biological processes. However, their roles and the mechanisms of action remain to be defined in disease conditions like diabetes and DKD. The pathogenesis of DKD is twofold, so is the principle of treatments. As the underlying disease, diabetes per se is the root cause of DKD and thus a primary focus of therapy. Meanwhile, aberrant molecular signaling in kidney parenchymal cells and inflammatory cells may directly contribute to DKD. Evidence suggests that a number of lncRNAs are centrally involved in development and progression of DKD either via direct pathogenic roles or as indirect mediators of some nephropathic pathways, like TGF-β1, NF-κB, STAT3 and GSK-3β signaling. Some lncRNAs are thus likely to serve as biomarkers for early diagnosis or prognosis of DKD or as therapeutic targets for slowing progression or even inducing regression of established DKD. Here, we elaborated the latest evidence in support of lncRNAs as a key player in DKD. In an attempt to strengthen our understanding of the pathogenesis of DKD, and to envisage novel therapeutic strategies based on targeting lncRNAs, we also delineated the potential mechanisms of action as well as the efficacy of targeting lncRNA in preclinical models of DKD.

Preventing and treating kidney disease in patients with type 2 diabetes

INTRODUCTION

Chronic kidney disease (CKD) represents a huge burden in patients with type 2 diabetes (T2DM). This review therefore has the aim of assessing the add-on value of new glucose-lowering agents compared or combined with inhibitors of the renin angiotensin aldosterone system (RAAS) on renal outcomes in T2DM patients.

AREAS COVERED

This article first summarizes the results reported with RAAS inhibitors, mainstay of nephroprotection in T2DM with albuminuria. Second, it describes the positive results with glucagon-like peptide-1 receptor agonists (GLP-1RAs) and, even more impressive, sodium-glucose cotransporter type 2 inhibitors (SGLT2is). Third, besides the potential of combined therapies, it briefly considers some new approaches currently in development.

EXPERT OPINION

RAAS inhibitors exert renoprotective effects beyond their blood pressure lowering effects while SGLT2is, and possibly GLP-1RAs, exert nephroprotection independently of their glucose-lowering activity. These effects were demonstrated not only on surrogate endpoints such as albuminuria and estimated glomerular filtration rate decline, but also on hard endpoints, including progression to end-stage renal disease requiring replacement therapy. The underlying mechanisms are different and potentially complementary on glomerular hemodynamics, arguing for combined therapies. Nevertheless, there is still room for new emerging drugs to tackle CKD in T2DM.

Diabetic gut microbiota dysbiosis as an inflammaging and immunosenescence condition that fosters progression of retinopathy and nephropathy

The increased prevalence of type 2 diabetes mellitus (T2DM) and life expectancy of diabetic patients fosters the worldwide prevalence of retinopathy and nephropathy, two major microvascular complications that have been difficult to treat with contemporary glucose-lowering medications. The gut microbiota (GM) has become a lively field research in the last years; there is a growing recognition that altered intestinal microbiota composition and function can directly impact the phenomenon of ageing and age-related disorders. In fact, human GM, envisaged as a potential source of novel therapeutics, strongly modulates host immunity and metabolism. It is now clear that gut dysbiosis and their products (e.g. p-cresyl sulfate, trimethylamine‑N‑oxide) dictate a secretory associated senescence phenotype and chronic low-grade inflammation, features shared in the physiological process of ageing ("inflammaging") as well as in T2DM ("metaflammation") and in its microvascular complications. This review provides an in-depth look on the crosstalk between GM, host immunity and metabolism. Further, it characterizes human GM signatures of elderly and T2DM patients. Finally, a comprehensive scrutiny of recent molecular findings (e.g. epigenetic changes) underlying causal relationships between GM dysbiosis and diabetic retinopathy/nephropathy complications is pinpointed, with the ultimate goal to unravel potential pathophysiological mechanisms that may be explored, in a near future, as personalized disease-modifying therapeutic approaches.