Elevated apolipoprotein C3 augments diabetic kidney disease and associated atherosclerosis in type 2 diabetes

Diabetes increases the risk of both cardiovascular disease and kidney disease. Notably, most of the excess cardiovascular risk in people with diabetes is in those with kidney disease. Apolipoprotein C3 (APOC3) is a key regulator of plasma triglycerides, and it has recently been suggested to play a role in both type 1 diabetes–accelerated atherosclerosis and kidney disease progression. To investigate if APOC3 plays a role in kidney disease in people with type 2 diabetes, we analyzed plasma levels of APOC3 from the Veterans Affairs Diabetes Trial. Elevated baseline APOC3 levels predicted a greater loss of renal function. To mechanistically test if APOC3 plays a role in diabetic kidney disease and associated atherosclerosis, we treated black and tan, brachyury, WT and leptin-deficient (OB; diabetic) mice, a model of type 2 diabetes, with an antisense oligonucleotide (ASO) to APOC3 or a control ASO, all in the setting of human-like dyslipidemia. Silencing APOC3 prevented diabetes-augmented albuminuria, renal glomerular hypertrophy, monocyte recruitment, and macrophage accumulation, partly driven by reduced ICAM1 expression. Furthermore, reduced levels of APOC3 suppressed atherosclerosis associated with diabetes. This suggests that targeting APOC3 might benefit both diabetes-accelerated atherosclerosis and kidney disease.


Supplemental Methods:
Glucose tolerance test Mice were fasted for 4-6 hours before injecting either 1 mg/body weight or 0.75 mg/g of glucose intraperioneally.Blood glucose was monitored at 0, 15, 30, 60 and 120 minutes after glucose administration.

Insulin tolerance test
Mice were fasted for 4-6 hours before injecting 2 mU/g body weight of human recomniant insulin intraperioneally.To avoid stress-induced hyperglycemia, mice were first subjected to a sham injection and blood collection prior to the actual injection of insulin (1).Blood glucose was monitored at 0, 15, 30, 60 and 120 minutes after glucose administration.

Pyruvate tolerance test
Mice were fasted for 6 hours before injecting 1.5 mg/g body weight of sodium pyruvate intraperioneally.Blood glucose was monitored at 0, 15, 30, 60 and 120 minutes after glucose administration.C. Area under each individual mouse's curve from the GTT.D-F.GTT, insulin tolerance test (ITT) and pyruvate tolerance test (PTT) in mice treated for 4 weeks with LDLR ASO and APOC3 ASO or cASO (4-week study).D. IP-GTT with 0.75 mg/g.E. IP-ITT using 2mU of insulin/g of body weight F. Pyruvate tolerance test with 1.5 mg pyruvate/g body weight.Data expressed increment in blood glucose over time point 0. G. Hepatic mRNA expression of G6pase from the 14week study (N=3-7).H. Hepatic mRNA expression of Pepck from the 14-week study (N=3-7).I. Pancreas insulin staining from the 14-week study (N=3-12).J. Glomerular silver methenamine stain in the 14-week study (N=8-21).K. Correlation between APOC3 and glomerular size on a per glomerulus size in OB mice only (n=48-92, from 5-7 mice).Data expressed as mean ± SEM.Data was analyzed by 2-WAY ANOVA followed by Tukey's multiple comparisons test.Text under the graph indicates the overall significance.N as indicated in Figure 5A unless otherwise noted.
treatment results in preservation of islet insulin.Mice were treated as in FigureS2.A. Fasting glucose.B. Intraperiontal (IP) glucose tolerance test (GTT) with 1 mg glucose/g body weight.

Table 1 :
Characteristics of people with diabetic nephropathy and non-diabetic controls

Table 8 :
Antibodies and key reagents