Investigation into the underlying molecular mechanisms of hypertensive nephrosclerosis using bioinformatics analyses

Preliminary Exploration of Potential Active Ingredients and Molecular Mechanisms of Yanggan Yishui Granules for Treating Hypertensive Nephropathy Using UPLC-Q-TOF/MS Coupled with Network Pharmacology and Molecular Docking Strategy

Hypertensive nephropathy (HN) is a prevalent complication of hypertension and stands as the second primary reason for end-stage renal disease. Research in clinical settings has revealed that Yanggan Yishui Granule (YGYSG) has significant therapeutic effects on HN. However, the material basis and action mechanisms of YGYSG against HN remain unclear. Consequently, this study utilized a comprehensive method integrating ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS), network pharmacology, and molecular docking to delineate the active ingredients and potential therapeutic mechanisms of YGYSG for treating HN. Firstly, sixty distinct components were recognized in total as potential active ingredients in YGYSG by UPLC-Q-TOF/MS. Subsequently, the mechanisms of YGYSG against HN were revealed for the first time using network pharmacology. 23 ingredients played key roles in the complete network and were the key active ingredients, which could affect the renin-angiotensin system, fluid shear stress and atherosclerosis, HIF-1 signaling pathway, and AGE-RAGE signaling pathway in diabetic complications by regulating 29 key targets such as TNF, IL6, ALB, EGFR, ACE, and MMP2. YGYSG could treat HN through the suppression of inflammatory response and oxidative stress, attenuating the proliferation of renal vascular smooth muscle cells, lessening glomerular capillary systolic pressure, and ameliorating renal dysfunction and vascular damage through the aforementioned targets and pathways. Molecular docking results revealed that most key active ingredients exhibited a high affinity for binding to the key targets. This study pioneers in clarifying the bioactive compounds and molecular mechanisms of YGYSG against HN and offers scientific reference into the clinical application.

Kinin B1 Receptor Mediates Renal Injury and Remodeling in Hypertension

Despite many readily available therapies, hypertensive kidney disease remains the second most prevalent cause of end-stage renal disease after diabetes, and continues to burden patient populations and escalate morbidity and mortality rates. Kinin B1 receptor (B1R) activation has been shown to have a role in the development of hypertension, one of the major etiologies for chronic kidney disease. However, the role of B1R in hypertension induced renal injury and remodeling remains unexplored. Using a DOCA-salt-induced hypertensive mouse model, we investigated whether B1R deficiency reduces hypertensive renal injury and fibrosis. To further recognize the translational role of B1R, we examined the expression of B1R and its correlation with collagen deposition in renal biopsies from control and hypertensive kidney disease patients. Our data indicates that renal B1R expression was upregulated in the kidneys of DOCA-salt hypertensive mice. Genetic ablation of B1R protected the mice from DOCA-salt-induced renal injury and fibrosis by preventing inflammation and oxidative stress in the kidney. Cultured human proximal tubular epithelial cells expressed B1R and stimulation of B1R with an agonist resulted in increased oxidative stress. In human kidney biopsy samples, we found that the B1R immunoreactivity was not only significantly increased in hypertensive patients compared to normotensive patients, but also there is a positive correlation between B1R expression and renal fibrosis levels. Taken together, our results identify a critical role of B1R in the development of inflammation and fibrosis of the kidney in hypertension.

Comprehensive Bioinformatics Analysis Identifies POLR2I as a Key Gene in the Pathogenesis of Hypertensive Nephropathy

Hypertensive nephropathy (HN), mainly caused by chronic hypertension, is one of the major causes of end-stage renal disease. However, the pathogenesis of HN remains unclarified, and there is an urgent need for improved treatments. Gene expression profiles for HN and normal tissue were obtained from the Gene Expression Omnibus database. A total of 229 differentially co-expressed genes were identified by weighted gene co-expression network analysis and differential gene expression analysis. These genes were used to construct protein–protein interaction networks to search for hub genes. Following validation in an independent external dataset and in a clinical database, POLR2I, one of the hub genes, was identified as a key gene related to the pathogenesis of HN. The expression level of POLR2I is upregulated in HN, and the up-regulation of POLR2I is positively correlated with renal function in HN. Finally, we verified the protein levels of POLR2I in vivo to confirm the accuracy of our analysis. In conclusion, our study identified POLR2I as a key gene related to the pathogenesis of HN, providing new insights into the molecular mechanisms underlying HN.

Introducing Serine as Cardiovascular Disease Biomarker Candidate via Pathway Analysis

Background:

The rate of death due to cardiovascular disease (CVD) is growing. Investigations about CVD that leading to introduce varieties of metabolites is available. The monitoring of these metabolites to find effective ones in the future of clinic applications is the main aim of this study.

Materials and Methods:

Numbers of 34 metabolites for the CVD are extracted from literature and designated for interaction determinations by MetScape V 3.1.3. The compound-reaction-enzyme-gene network was constructed and the pathways were analyzed. Based on the presence of metabolites in the pathways the critical compounds were determined.

Results:

Pathway analysis revealed 18 disturbed pathways related to the CVD. glycerophospholipid metabolism pathway including 27 compounds is related to the 9 queried metabolites. L-Serine which was communed between 5 pathways and also was presented in the largest pathway was identified as the critical compound.

Conclusion:

It can be concluded that L-Serine is a proper biomarker candidate for CVD diagnosis and also patients follow up approaches.

Silencing of TXNIP Alleviated Oxidative Stress Injury by Regulating MAPK-Nrf2 Axis in Ischemic Stroke

Ischemic stroke is a life-threatening cerebrovascular thrombotic disease, oxidative stress is considered to be a critical factor to stroke pathophysiology. This study aimed to investigate the underlying molecular mechanism and propose the potential therapeutic strategy for ischemic stroke. Bioinformatics analysis based on a public microarray profile (GSE 61616) of ischemic stroke rats was performed as a pilot research. Oxidative stress was enriched as a significantly gene ontology item, and thioredoxin-interacting protein (TXNIP) and MAPK signaling were identified as the hub gene and pathway, respectively. The experiments in middle cerebral artery occlusion rats demonstrated that ischemia induced the activation of oxidative stress. The expressions of TXNIP, p-p38, p-JNK, p-ERK were significantly increased while Nrf2 and HO-1 expressions were decreased after stroke. Rescue assays were conducted in primary cultured neurons to explore the accurate interrelations among these factors. The results indicated that MAPK specific inhibitor and siRNA-TXNIP significantly alleviated the oxidative stress injury induced by oxygen-glucose deprivation. In addition, knocking down of TXNIP inhibited the activation of MAPK pathway and promoted Nrf2 pathway. Taken together, these findings indicated that TXNIP aggravated the oxidative stress injury by regulating MAPK-Nrf2 axis in ischemic stroke. Silencing of TXNIP seems a promising therapeutic strategy to alleviate ischemic stroke.

Gene Expression Studies and Targeted Metabolomics Reveal Disturbed Serine, Methionine, and Tyrosine Metabolism in Early Hypertensive Nephrosclerosis

Introduction

Hypertensive nephrosclerosis is among the leading causes of end-stage renal disease, but its pathophysiology is poorly understood. We wanted to explore early metabolic changes using gene expression and targeted metabolomics analysis.

Methods

We analyzed gene expression in kidneys biopsied from 20 patients with nephrosclerosis and 31 healthy controls with an Affymetrix array. Thirty-one amino acids were measured by liquid chromatography coupled with mass spectrometry (LC-MS) in urine samples from 62 patients with clinical hypertensive nephrosclerosis and 33 age- and sex-matched healthy controls, and major findings were confirmed in an independent cohort of 45 cases and 15 controls.

Results

Amino acid catabolism and synthesis were strongly underexpressed in hypertensive nephrosclerosis (13- and 7-fold, respectively), and these patients also showed gene expression patterns indicating decreased fatty acid oxidation (12-fold) and increased interferon gamma (10-fold) and cellular defense response (8-fold). Metabolomics analysis revealed significant distribution differences in 11 amino acids in hypertensive nephrosclerosis, among them tyrosine, phenylalanine, dopamine, homocysteine, and serine, with 30% to 70% lower urine excretion. These findings were replicated in the independent cohort. Integrated gene-metabolite pathway analysis showed perturbations of renal dopamine biosynthesis. There were also significant differences in homocysteine/methionine homeostasis and the serine pathway, which have strong influence on 1-carbon metabolism. Several of these disturbances could be interconnected through reduced regeneration of tetrahydrofolate and tetrahydrobiopterin.

Conclusion

Early hypertensive nephrosclerosis showed perturbations of intrarenal biosynthesis of dopamine, which regulates natriuresis and blood pressure. There were also disturbances in serine/glycine and methionine/homocysteine metabolism, which may contribute to endothelial dysfunction, atherosclerosis, and renal fibrosis.