lc15-0444 and Inflammation

Non-alcoholic fatty liver disease (NAFLD) includes a broad spectrum of liver diseases characterized by steatosis, inflammation, and fibrosis. This study aimed to investigate the potential of dipeptidyl peptidase-4 inhibitors and sodium-glucose cotransporter 2 inhibitors in alleviating the progression of NAFLD. The NAFLD model was generated by feeding male C57BL/6J mice a choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) for 7 weeks. After 2 weeks of CDAHFD feeding, the NAFLD model mice were assigned to four groups, namely (ⅰ) VEHICLE, (ⅱ) gemigliptin (GEMI), (ⅲ) empagliflozin (EMPA), and (ⅳ) GEMI + EMPA. For the next 5 weeks, mice received the vehicle or the drug based upon the group to which they belonged. Thereafter, the triglyceride concentration, extent of fibrosis, and the expression of genes encoding inflammatory cytokines, chemokines, and antioxidant enzymes were analyzed in the livers of mice. The NAFLD activity score and hepatic fibrosis grade were assessed via hematoxylin and eosin and Sirius Red staining of the liver tissue samples. All mice belonging to the GEMI, EMPA, and GEMI + EMPA groups showed improvements in the accumulation of liver triglycerides and the expression of inflammatory cytokines and chemokines. Additionally, the oxidative stress was reduced due to inhibition of the c-Jun N-terminal kinase pathway and upregulation of the antioxidant enzymes. Furthermore, in these three groups, the galectin-3 and interleukin 33-induced activity of tumor necrosis factor-α was inhibited, thereby preventing the progression of liver fibrosis. These findings suggest that the GEMI, EMPA, and GEMI + EMPA treatments ameliorate hepatic steatosis, inflammation, oxidative stress, and fibrosis in CDAHFD-induced NAFLD mouse models.

Topics: Amino Acids; Animals; Benzhydryl Compounds; Choline; Cytokines; Diet, High-Fat; Disease Models, Animal; Disease Progression; Glucosides; Inflammation; Inflammation Mediators; JNK Mitogen-Activated Protein Kinases; Liver; Macrophage Activation; Male; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Oxidative Stress; Phosphorylation; Piperidones; Protective Agents; Pyrimidines

The hypoglycemic drugs dipeptidyl peptidase-4 (DPP-4) inhibitors have proven protective effects on diabetic kidney disease, including renal fibrosis. Although NOD-like receptor protein 3 (NLRP3) inflammasome activation is known to play an important role in the progression of renal fibrosis, the impact of DPP-4 inhibition on NLRP3-mediated inflammation while ameliorating renal fibrosis has not been fully elucidated. Here, we report that the renoprotective effect of gemigliptin is associated with a reduction in NLRP3-mediated inflammation in a murine model of renal fibrosis.. We examined the effects of gemigliptin on renal tubulointerstitial fibrosis induced in mice by unilateral ureteral obstruction (UUO). Using immunohistochemical and Western blot analysis, we quantitated components of the NLRP3 inflammasome in kidneys with and without gemigliptin treatment, and. Immunohistological examination revealed that gemigliptin ameliorated UUO-induced tubular atrophy and renal fibrosis. Gemigliptin-treated kidneys showed a reduction in levels of NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), caspase-1, and interleukin-1β, which had all been markedly increased by UUO. In line with the. The present study shows that activation of the NLRP3 inflammasome contributes to UUO-induced renal fibrosis and the renoprotective effect of gemigliptin is associated with attenuation of NLRP3 inflammasome activation.

Topics: Administration, Oral; Animals; Cell Line; Diabetic Nephropathies; Dipeptidyl-Peptidase IV Inhibitors; Down-Regulation; Fibrosis; Humans; Inflammasomes; Inflammation; Kidney Tubules, Proximal; Mice; Mice, Inbred C57BL; NLR Family, Pyrin Domain-Containing 3 Protein; Piperidones; Protective Agents; Pyrimidines; Signal Transduction; Transforming Growth Factor beta; Ureteral Obstruction

Topics: Acute Kidney Injury; Animals; Apoptosis; Disease Models, Animal; Doxorubicin; Humans; Inflammation; Kidney Diseases; Male; Membrane Proteins; Mice; Oxidative Stress; Piperidones; Pyrimidines; Repressor Proteins; WT1 Proteins

Dipeptidyl peptidase 4 (DPP-4) inhibitors are widely used antihyperglycemic agents for type 2 diabetes mellitus. Recently, increasing attention has been focused on the pleiotropic actions of DPP-4 inhibitors. The aim of the present study was to examine whether gemigliptin, a recently developed DPP-4 inhibitor, could ameliorate features of metabolic syndrome. Mice were fed a Western diet (WD) for 12 weeks and were subsequently divided into 2 groups: mice fed a WD diet alone or mice fed a WD diet supplemented with gemigliptin for an additional 4 weeks. Gemigliptin treatment attenuated WD-induced body mass gain, hypercholesterolemia, adipocyte hypertrophy, and macrophage infiltration into adipose tissue, which were accompanied by an increased expression of uncoupling protein 1 in subcutaneous fat. These events contributed to improved insulin sensitivity, as assessed by the homeostasis model assessment of insulin resistance and intraperitoneal insulin tolerance test. Furthermore, gemigliptin reduced WD-induced hepatic triglyceride accumulation via inhibition of de novo lipogenesis and activation of fatty acid oxidation, which was accompanied by AMP-dependent protein kinase activation. Gemigliptin ameliorated WD-induced hepatic inflammation and fibrosis through suppression of oxidative stress. These results suggest that DPP-4 inhibitors may represent promising therapeutic agents for metabolic syndrome beyond their current role as antihyperglycemic agents.

Topics: Adipocytes; Animals; Diet, Western; Fatty Liver; Fibrosis; Hypercholesterolemia; Hypertrophy; Inflammation; Insulin Resistance; Liver; Male; Metabolic Syndrome; Mice; Piperidones; Pyrimidines; Subcutaneous Fat; Uncoupling Protein 1; Weight Gain

The direct effects of dipeptidyl peptidase-IV (DPP-IV) inhibitors on endoplasmic reticulum (ER) stress-induced apoptosis and inflammation in cardiomyocytes have not been elucidated. H9c2 cell viability, which was reduced by tunicamycin, was increased after DPP-IV inhibitor gemigliptin treatment. Gemigliptin significantly decreased the tunicamycin-mediated increase in glucose regulated protein 78 (GRP78) expression and ER stress-mediated signaling molecules such as protein kinase RNA-like endoplasmic reticulum kinase (PERK)/C-EBP homologous protein (CHOP) and inositol-requiring enzyme 1α (IRE1α)/c-Jun N-terminal kinase (JNK)-p38. Furthermore, gemigliptin effectively induced Akt phosphorylation in a dose-dependent manner. Using flow cytometry and Hoechst staining, we showed that treatment with Akt inhibitor significantly blocked the anti-apoptotic effects mediated by gemigliptin. The reduction in tunicamycin-induced GRP78 level and PERK/CHOP pathway activity by gemigliptin was reversed after treatment with Akt inhibitor. In conclusion, gemigliptin effectively inhibited ER stress-induced apoptosis and inflammation in cardiomyocytes via Akt/PERK/CHOP and IRE1α/JNK-p38 pathways, suggesting its direct protective role in cardiovascular diseases.

Topics: Animals; Apoptosis; Cell Line; Cytokines; Dipeptidyl-Peptidase IV Inhibitors; eIF-2 Kinase; Endoplasmic Reticulum Stress; Endoribonucleases; Inflammation; Inflammation Mediators; Models, Biological; Multienzyme Complexes; Myocytes, Cardiac; Phosphorylation; Piperidones; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-akt; Pyrimidines; Rats; RNA, Messenger; Signal Transduction; Transcription, Genetic; Tunicamycin