Utility of Serum miR-122, Liver Enzymes, and Hepatic Histopathology in Response to Hepatotoxicants in Sprague-Dawley Rats

Urinary miRNA profiles in chronic kidney injury - Benefits of extracellular vesicle enrichment and miRNAs as potential biomarkers for renal fibrosis, glomerular injury and endothelial dysfunction

Micro-RNAs (miRNAs) are regulators of gene expression and play an important role in physiological homeostasis and disease. In biofluids miRNAs can be found in protein complexes or in extracellular vesicles (EVs). Altered urinary miRNAs are reported as potential biomarkers for chronic kidney disease (CKD). In this context we compared established urinary protein biomarkers for kidney injury with urinary miRNA profiles in obese ZSF1 and hypertensive renin transgenic rats. Additionally, the benefit of urinary EV enrichment was investigated in vivo and the potential association of urinary miRNAs with renal fibrosis in vitro. Kidney damage in both rat models was confirmed by histopathology, proteinuria, and increased levels of urinary protein biomarkers. In total 290 miRNAs were elevated in obese ZSF1 rats compared to lean controls, while 38 miRNAs were altered in obese ZSF1 rats during 14 to 26 weeks of age. These 38 miRNAs correlated better with disease progression than established urinary protein biomarkers. MiRNAs increased in obese ZSF1 rats were associated with renal inflammation, fibrosis, and glomerular injury. Eight miRNAs were also changed in urinary EVs of renin transgenic rats, including one which might play a role in endothelial dysfunction. EV enrichment increased the number and detection level of several miRNAs implicated in renal fibrosis in vitro and in vivo. Our results show the benefit of EV enrichment for miRNA detection and the potential of total urine and urinary EV-associated miRNAs as biomarkers of altered kidney physiology, renal fibrosis and glomerular injury, and disease progression in hypertension and obesity induced CKD.

Identification of miR-199a-5p, miR-214-3p and miR-99b-5p as Fibrosis-Specific Extracellular Biomarkers and Promoters of HSC Activation

Liver fibrosis is characterized by the accumulation of extracellular matrix (ECM) resulting in the formation of fibrous scars. In the clinic, liver biopsies are the standard diagnostic method despite the potential for clinical complications. miRNAs are single-stranded, non-coding RNAs that can be detected in tissues, body fluids and cultured cells. The regulation of many miRNAs has been linked to tissue damage, including liver fibrosis in patients, resulting in aberrant miRNA expression/release. Experimental evidence also suggests that miRNAs are regulated in a similar manner in vitro and could thus serve as translational in vitro–in vivo biomarkers. In this work, we set out to identify and characterize biomarkers for liver fibrosis that could be used in vitro and clinically for research and diagnostic purposes. We focused on miRNAs released from hepatic 3D cultures exposed to methotrexate (MTX), which causes fibrosis, and acetaminophen (APAP), an acute hepatotoxicant with no clinically relevant association to liver fibrosis. Using a 3D in vitro model, we corroborated compound-specific responses as we show MTX induced a fibrotic response, and APAP did not. Performing miRNA-seq of cell culture supernatants, we identified potential miRNA biomarkers (miR-199a-5p, miR-214-3p, niRNA-125a-5p and miR-99b-5p) that were associated with a fibrotic phenotype and not with hepatocellular damage alone. Moreover, transfection of HSC with miR-199a-5p led to decreased expression of caveolin-1 and increased α-SMA expression, suggesting its role in HSC activation. In conclusion, we propose that extracellular miR-214-3p, miR-99b-5p, miR-125a-5p and specifically miR-199a-5p could contribute towards a panel of miRNAs for identifying liver fibrosis and that miR-199a-5p, miR-214-3p and miR-99b-5p are promoters of HSC activation.

MiR-122-5p knockdown protects against APAP-mediated liver injury through up-regulating NDRG3

MiR-122-5p serves as a novel biomarker for drug-induced liver injury (DILI), but its function in DILI remains unclear. The present study, therefore, explored the function and potential mechanism of miR-122-5p in DILI. Sprague-Dawley (SD) rats were treated with miR-122-5p antagomir, and then DILI was induced in the rats by acetaminophen (APAP). To determine the effect of miR-122-5p on DILI in vivo, liver injury was examined by HE staining and TUNEL assays, and the levels of serum ALT and AST were determined using an automated clinical chemistry analyzer. To further reveal the mechanism of miR-122-5p in DILI, THLE-2 (normal liver cell line) cells were transfected with miR-122-5p mimic and inhibitor, NDRG3, and siNDRG3, and then injured by APAP. The relationship between miR-122-5p and NDRG3 was determined by TargetScan, luciferase reporter assay, and Western blot. The viability and apoptosis of THLE-2 cells were detected by CCK-8 and flow cytometry, respectively. The levels of mRNA and protein in vivo and in vitro were measured by qRT-PCR and Western blot, respectively. APAP induced liver injury and increased the levels of ALT, AST, and miR-122-5p in DILI rats. However, these effects of APAP were attenuated by miR-122-5p antagomir. MiR-122-5p negatively regulated NDRG3 expression. APAP decreased cell viability, apoptosis resistance, and Bcl-w and Bcl-2 levels whereas increased Bax level in THLE-2 cells. However, these effects of APAP on THLE-2 cells were promoted by miR-122-5p up-regulation but inhibited by miR-122-5p knockdown. MiR-122-5p knockdown protects against APAP-mediated liver injury through up-regulating NDRG3.

Mechanism of isoniazid-induced hepatotoxicity in zebrafish larvae: Activation of ROS-mediated ERS, apoptosis and the Nrf2 pathway

Isoniazid (INH) is a first-line anti-tuberculosis drug. INH has been detected in surface waters which may create a risk to aquatic organisms. In this study, the hepatotoxicity of INH was elucidated using zebrafish. The liver morphology, transaminase level, redox-related enzyme activity, reactive oxygen species (ROS) content and mRNA levels of liver injury-related genes were measured. The results showed that INH (4, 6 mM) significantly caused liver atrophy and increased levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in zebrafish. INH (6 mM) led to decreased catalase (CAT) activity, glutathione peroxidase (GPx) activity and glutathione (GSH) content but increased ROS and malondialdehyde (MDA) levels. Moreover, INH (6 mM) decreased expression levels of miR-122 and pparα but increased mRNA levels of ap-1 and c-jun. Furthermore, mRNA levels of factors related to endoplasmic reticulum stress (ERS) (grp78, atf6, perk, ire1, xbp1s and chop), apoptosis (bax, cyt, caspase-3, caspase-8 and caspase-9) and the Nrf2 signalling pathway (nrf2, ho-1, nqo1, gclm and gclc) were significantly upregulated. INH may act on hepatotoxicity in zebrafish by increasing ROS content, which weakens the antioxidant capacity, leading to ERS, cell apoptosis and liver injury. In addition, the Nrf2 signalling pathway is activated as a stress compensation mechanism during INH-induced liver injury, but it is not sufficient to counteract INH-induced hepatotoxicity.