Teneligliptin mitigates diabetic cardiomyopathy by inhibiting activation of the NLRP3 inflammasome

Abstract

Background: Diabetic cardiomyopathy (DCM), which is a complication of diabetes, poses a great threat to public health. Recent studies have confirmed the role of NLRP3 (NOD-like receptor protein 3) activation in DCM development through the inflammatory response. Teneligliptin is an oral hypoglycemic dipeptidyl peptidase-IV inhibitor used to treat diabetes. Teneligliptin has recently been reported to have anti-inflammatory and protective effects on myocardial cells.

Aim: To examine the therapeutic effects of teneligliptin on DCM in diabetic mice.

Methods: Streptozotocin was administered to induce diabetes in mice, followed by treatment with 30 mg/kg teneligliptin.

Results: Marked increases in cardiomyocyte area and cardiac hypertrophy indicator heart weight/tibia length reductions in fractional shortening, ejection fraction, and heart rate; increases in creatine kinase-MB (CK-MB), aspartate transaminase (AST), and lactate dehydrogenase (LDH) levels; and upregulated NADPH oxidase 4 were observed in diabetic mice, all of which were significantly reversed by teneligliptin. Moreover, NLRP3 inflammasome activation and increased release of interleukin-1β in diabetic mice were inhibited by teneligliptin. Primary mouse cardiomyocytes were treated with high glucose (30 mmol/L) with or without teneligliptin (2.5 or 5 µM) for 24 h. NLRP3 inflammasome activation. Increases in CK-MB, AST, and LDH levels in glucose-stimulated cardiomyocytes were markedly inhibited by teneligliptin, and AMP (p-adenosine 5'-monophosphate)-p-AMPK (activated protein kinase) levels were increased. Furthermore, the beneficial effects of teneligliptin on hyperglycaemia-induced cardiomyocytes were abolished by the AMPK signaling inhibitor compound C.

Conclusion: Overall, teneligliptin mitigated DCM by mitigating activation of the NLRP3 inflammasome.

Keywords: AMPK; Diabetic cardiomyopathy; Interleukin-1β; NLRP3; Teneligliptin.

Figure 1

Teneligliptin ameliorated myocardial hypertrophy in streptozotocin-induced diabetic mice. A: Molecular structure of teneligliptin; B: Quantitative analysis of cardiomyocyte area; C: Heart weight/tibia length. ^aP < 0.05 vs control group; ^bP < 0.05 vs streptozotocin group, n = 8. STZ: Streptozotocin.

Figure 2

Teneligliptin improved heart function in streptozotocin-induced diabetic mice. A: The results of HE staining, Scale bar = 50 µm; B-D: Mice heart fractional shortening, ejection fraction, and heart rate was measured by echo. ^aP < 0.05 vs control group; ^bP < 0.05 vs streptozotocin group, n = 8. STZ: Streptozotocin.

Figure 3

Teneligliptin reduced the expression of the myocardial injury indicators in streptozotocin-induced diabetic mice. A: Creatine kinase-MB level; B: The aspartate transaminase level; C: The lactate dehydrogenase level. ^aP < 0.05 vs control group; ^bP < 0.05 vs streptozotocin group, n = 8. STZ: Streptozotocin; CK-MB: Creatine kinase-MB; AST: Aspartate transaminase; LDH: Lactate dehydrogenase.

Figure 4

Teneligliptin reduced the expression of NOX4 in diabetic mice. A: mRNA of NOX-4; B: Protein of NOX-4; C: Quantitative analysis of protein expression levels for panel B. ^aP < 0.05 vs control group; ^bP < 0.05 vs streptozotocin group, n = 8. STZ: Streptozotocin.

Figure 5

Teneligliptin reduced activation of the cardiac NLRP3 inflammasome in the control and diabetic mice. A: NLRP3 and caspase-1 measured by Western blot assays; B: Quantitative analysis of protein expression levels for panel A; C: Production of interleukin-1β as measured by ELISA. ^aP < 0.05 vs control group; ^bP < 0.05 vs streptozotocin group, n = 8. STZ: Streptozotocin.

Figure 6

Teneligliptin prevented activation of the cardiac NLRP3 inflammasome and injury in cardiomyocytes. Primary cardiomyocytes were treated with high glucose (30 mmol/L) with or without teneligliptin (2.5 or 5 µM) for 24 h. A: Expression of NLRP3 and caspase-1 were measured by western blot assays; B: Levels of IL-1β as measured by ELISA; C: Levels of creatine kinase-MB and aspartate transaminase level. ^aP < 0.05 vs control group; ^bP < 0.05 vs high glucose 30 mmol/L group; ^cP < 0.05 vs high glucose 0 mmol/L + teneligliptin 0 µM group; ^dP < 0.05 vs high glucose 30 mmol/L + teneligliptin 0 µM group, n = 5. CK-MB: Creatine kinase-MB; AST: Aspartate transaminase; IL: Interleukin.

Figure 7

Teneligliptin increased the phosphorylation of AMPK against high glucose in cardiomyocytes. Primary cardiomyocytes were treated with high glucose (30 mmol/L) with or without teneligliptin (2.5 or 5 µM) for 24 h. Levels of p-AMPK were measured by western blot assays. ^aP < 0.05 vs control group; ^bP < 0.05 vs high glucose 30 mmol/L + teneligliptin 0 µM group, n = 5.

Figure 8

Inhibition of AMPK abolished the beneficial effects of teneligliptin against high glucose in cardiomyocytes. Primary cardiomyocytes were treated with high glucose (30 mmol/L) with or without teneligliptin (5 µM) and compound C (10 μM). A: Levels of p-AMPK; B: The levels of NLRP3; C: Levels of creatine kinase-MB and aspartate transaminase level. ^aP < 0.05 vs control group; ^bP < 0.05 vs high glucose 30 mmol/L group; ^cP < 0.05 vs high glucose 30 mmol/L + teneligliptin 5 µM group, n = 5.