Urine Cell Transcriptomes Implicate Specific Renal Inflammatory Pathways Associated With Difficult-to-Control Hypertension.

Background The renal mechanisms involved in the maintenance of human hypertension and resistance to treatment are not well understood. Animal studies suggest that chronic renal inflammation contributes to hypertension. We studied cells shed in first-morning urine samples from individuals who were hypertensive who exhibited difficult-to-control blood pressure (BP). We performed bulk RNA sequencing of these shed cells to develop transcriptome-wide associations with BP. We also analyzed nephron-specific genes and used an unbiased bioinformatic approach to find signaling pathways activated in difficult-to-control hypertension. Methods and Results Participants who completed the SPRINT (Systolic Blood Pressure Intervention Trial) at a single trial site were recruited, and cells shed in first-morning urine samples collected. A total of 47 participants were divided into 2 groups based on hypertension control. The BP-difficult group (n=29) had systolic BP>140 mm Hg, >120 mm Hg after intensive treatment for hypertension, or required more than the median number of antihypertensive drugs used in SPRINT. The easy-to-control BP group (n=18) comprised the remainder of the participants. A total of 60 differentially expressed genes were identified with a >2-fold change in the BP-difficult group. In BP-difficult participants, 2 of the most upregulated genes were associated with inflammation: Tumor Necrosis Factor Alpha Induced Protien 6 (fold change, 7.76; P=0.006) and Serpin Family B Member 9 (fold change, 5.10; P=0.007). Biological pathway analysis revealed an overrepresentation of inflammatory networks, including interferon signaling, granulocyte adhesion and diapedesis, and Janus Kinase family kinases in the BP-difficult group (P<0.001). Conclusions We conclude that transcriptomes from cells shed in first-morning urine identify a gene expression profile in difficult-to-control hypertension that associates with renal inflammation.

Glibenclamide induces collagen IV catabolism in high glucose-stimulated mesangial cells.

We have shown the full prevention of mesangial expansion in insulin-deficient diabetic rats by treatment with clinically-relevant dosages of glibenclamide (Glib). Studies in mesangial cells (MCs) also demonstrated reduction in the high glucose (HG)-induced accumulation of collagens, proposing that this was due to increased catabolism. In the present study, we investigated the signaling pathways that may be implicated in Glib action. Rat primary MCs were exposed to HG for 8 weeks with or without Glib in therapeutic (0.01 µM) or supratherapeutic (1.0 µM) concentrations. We found that HG increased collagen IV protein accumulation and PAI-1 mRNA and protein expression, in association with decreased cAMP generating capacity and decreased PKA activity. Low Glib increased collagen IV mRNA but fully prevented collagen IV protein accumulation and PAI-1 overexpression while enhancing cAMP formation and PKA activity. MMP2 mRNA, protein expression and gelatinolytic activity were also enhanced. High Glib was, overall, ineffective. In conclusion, low dosage/concentration Glib prevents HG-induced collagen accumulation in MC by enhancing collagen catabolism in a cAMP-PKA-mediated PAI-1 inhibition.

Effects of sulfonylureas, alpha-endosulfine counterparts, on glomerulosclerosis in type 1 and type 2 models of diabetes.

BACKGROUND: Previously, we showed the expression of a unique sulfonylurea receptor (SUR) and its putative endogenous ligand, alpha-endosulfine, in mesangial cells and isolated glomeruli. Further, this ligand was up-regulated by high glucose concentration. To investigate the possible role of alpha-endosulfine up-regulation in diabetes, we administered sulfonylureas, the exogenous ligands of SUR, to diabetic animals. METHODS: In streptozotocin-induced, insulin-deficient, diabetic rats, glomerulosclerosis, albuminuria, glomerular expression of fibronectin mRNA, and glomerular filtration rate (GFR) were studied for various periods up to 36 weeks. Several rat groups received either glibenclamide or tolazamide during the entire study period. Also, glomerulosclerosis and albuminuria were determined in insulin-resistant db/db mice, at 26 weeks of treatment with tolazamide. RESULTS: Sulfonylureas did not improve hyperglycemia or reduce glycosylated hemoglobin levels. In insulin-deficient diabetic rats, sulfonylureas significantly decreased the degree of glomerulosclerosis and completely reversed the enhanced albumin excretion. Also, glibenclamide reduced diabetes-induced glomerular overexpression of fibronectin mRNA. Because glibenclamide may improve the afferent arteriolar dilatation of diabetes, thereby reducing glomerular hyperfiltration, its effect on GFR was determined. Glibenclamide did not alter glomerular hyperfiltration or renal hypertrophy, regardless of the intensity of hyperglycemia. Finally, in insulin-resistant mice, tolazamide did not alter the extent of diabetic glomerulosclerosis or increased albuminuria. CONCLUSION: Long-term treatment with sulfonylureas completely prevents glomerular injury in insulin-deficient diabetes in rats. However, this protective effect is not demonstrable in an insulin-resistant model of the disease. We postulate that mesangial alpha-endosulfine up-regulation in the hyperglycemic milieu of insulin-deficient diabetes may retard glomerular extracellular matrix formation and mesangial expansion.