Urinary expression of long non‑coding RNA TUG1 in non‑diabetic patients with glomerulonephritides

Metabolic alterations serve a significant role in the pathogenesis of kidney disease. Long non-coding RNA (lncRNA) taurine upregulated gene 1 (TUG1) is a known regulator of podocyte health and mitochondrial biogenesis. Although TUG1 protects against podocyte loss in models of diabetic nephropathy, it is unknown if urinary TUG1 expression is associated with clinical and histopathological findings in non-diabetic patients diagnosed with glomerulonephritides. In the present study, the expression of TUG1, podocyte-specific markers (nephrin and podocin) and mitochondrial biogenesis-associated mRNAs (transcription factor A mitochondrial, cytochrome C oxidase subunit 5A and peroxisome proliferator-activated receptor γ coactivator 1α) were examined in urinary sediment of non-diabetic patients with biopsy-confirmed glomerulonephritides and healthy controls. Urinary expression of TUG1 was significantly lower in patients with glomerulonephritides, particularly those diagnosed with Focal Segmental Glomerulosclerosis (FSGS). Furthermore, TUG1 levels were associated with urinary expression of podocyte-specific markers and mRNAs associated with mitochondrial biogenesis. Loss of TUG1 expression in urinary sediment was strongly associated with FSGS, highlighting the potential of this lncRNA and its mitochondrial biogenesis-associated targets as non-invasive biomarkers of assessing podocytopathy.