Lifestyle Intervention for Weight Loss and Cardiometabolic Changes in the Setting of Glucokinase Regulatory Protein Inhibition: Glucokinase Regulatory Protein-Leu446Pro Variant in Look AHEAD

En masse organoid phenotyping informs metabolic-associated genetic susceptibility to NASH

Genotype-phenotype associations for common diseases are often compounded by pleiotropy and metabolic state. Here, we devised a pooled human organoid-panel of steatohepatitis to investigate the impact of metabolic status on genotype-phenotype association. En masse population-based phenotypic analysis under insulin insensitive conditions predicted key non-alcoholic steatohepatitis (NASH)-genetic factors including the glucokinase regulatory protein (GCKR)-rs1260326:C>T. Analysis of NASH clinical cohorts revealed that GCKR-rs1260326-T allele elevates disease severity only under diabetic state but protects from fibrosis under non-diabetic states. Transcriptomic, metabolomic, and pharmacological analyses indicate significant mitochondrial dysfunction incurred by GCKR-rs1260326, which was not reversed with metformin. Uncoupling oxidative mechanisms mitigated mitochondrial dysfunction and permitted adaptation to increased fatty acid supply while protecting against oxidant stress, forming a basis for future therapeutic approaches for diabetic NASH. Thus, "in-a-dish" genotype-phenotype association strategies disentangle the opposing roles of metabolic-associated gene variant functions and offer a rich mechanistic, diagnostic, and therapeutic inference toolbox toward precision hepatology. VIDEO ABSTRACT.

Distinguishing the lipid profile of GCK-MODY patients and its correlation with hsCRP levels

AIMS

Glucokinase-maturity-onset diabetes of the young (GCK-MODY) is the most common monogenic diabetes in China. We have previously reported on the low levels of high-sensitivity C-reactive protein (hsCRP) in patients with GCK-MODY. In this study, we further explored the correlation between the serum lipid profiles and hsCRP levels of patients with different types of diabetes. We also proposed to determine the possible mechanism of macrovascular protection in GCK genetic variants.

METHODS

The serum lipid profiles of the GCK-MODY group (n = 50) were compared with those of the hepatocyte nuclear factor-1 alpha (HNF1A)-MODY group (n = 19), the type 1 diabetes (T1D) group (n = 50), and the type 2 diabetes (T2D) group (n = 54). The associations between the lipid compositions and the hsCRP levels in each group were also explored.

RESULTS

Elevated levels of high-density lipoprotein cholesterol (HDL-C) were found in the GCK-MODY group (1.5 ± 0.27) compared with the T1D (1.2 ± 0.47, p < 0.01) and T2D (1.3 ± 0.3, p < 0.01) groups. On the other hand, a significantly lower LDL-C level (2.4 ± 0.69) in the GCK-MODY group compared with the T1D (2.7 ± 0.72, p < 0.01) and T2D (2.9 ± 0.68, p < 0.01) groups was also noted. A lower ratio of triglyceride to HDL-C (TG/HDL) and a lower hsCRP level were also found in the GCK-MODY group [TG/HDL = 0.38 (0.25-0.52), hsCRP = 0.2 mg/L (0.16-0.37)] compared with the T1D group [(TG/HDL = 0.56 (0.39-1.29), hsCRP = 0.56 mg/L (0.39-1.29), p < 0.01] and the T2D group [(TG/HDL = 1.6 (1.1-2.68), hsCRP = 1.11 mg/L (0.66-2.34), p < 0.01]. Although patients with HNF1A-MODY showed similar hsCRP levels [0.17 (0.08-0.52), p > 0.05] compared with the patients in the GCK-MODY group, they had higher TG levels [1.01 (0.66-1.76), p < 0.05] and TG/HDL ratios [0.84 (0.56-1.31), p < 0.05]. Analysis of the correlations between the hsCRP levels and lipid profiles of each group confirmed that the LnhsCRP (natural logarithm-transformed hsCRP level) was positively correlated with the LnTG (natural logarithm-transformed TG) (r = 0.352, p = 0.011) and the Ln(TG/HDL) ratio (r = 0.283, p = 0.047) only in individuals with GCK-MODY.

CONCLUSIONS

Individuals harboring GCK variants have the characteristics of protective lipid profiles manifested as a higher level of HDL-C and a lower level of LDL-C compared with type 1 and 2 diabetes milletus (T1DM and T2DM, respectively) patients. In addition, lower ratios of TG/HDL were found to be associated with the inhibition of secretion of hsCRP, even when adjusted for the HbA1c levels in patients with GCK-MODY. It is suggested that the protective effect of macrovascular complications in GCK-MODY patients might partly be due to their unique lipid profiles associated with the suppression of inflammation.

The Combined Effect of Polygenic Risk from FTO and ADRB2 Gene Variants, Odds of Obesity, and Post-Hipcref Diet Differences

BACKGROUND

Computing polygenic risk scores (PRS) to predict the degree of risk for obesity may contribute to weight management programs strategically.

OBJECTIVES

To investigate the combined effect of FTO rs9930501, rs9930506, and rs9932754 and ADRB2 rs1042713 and rs1042714 using PRS on (1) the odds of obesity and (2) post-intervention differences in dietary, anthropometric, and cardiometabolic parameters in response to high-protein calorie-restricted, high-vitamin E, high-fiber (Hipcref) diet intervention in Malaysian adults.

METHODS

Both a cross-sectional study (n = 178) and a randomized controlled trial (RCT) (n = 128) were conducted to test the aforementioned objectives. PRS was computed as the weighted sum of the risk alleles possessed by each individual participant. Participants were stratified into first (PRS 0-0.64), second (PRS 0.65-3.59), and third (PRS 3.60-8.18) tertiles.

RESULTS

The third tertile of PRS was associated with significantly higher odds of obesity: 2.29 (95% CI = 1.11-4.72, adjusted p = 0.025) compared to the first tertile. Indians (3.9 ± 0.3) had significantly higher PRS compared to Chinese (2.1 ± 0.4) (p = 0.010). In the RCT, a greater reduction in high-sensitivity C-reactive protein (hsCRP) levels was found in second and third tertiles after Hipcref diet intervention compared to the control diet (p interaction = 0.048).

CONCLUSION

Higher PRS was significantly associated with increased odds of obesity. Individuals with higher PRS had a significantly greater reduction in hsCRP levels after Hipcref diet compared to the control diet.

Blood triglyceride levels are associated with DNA methylation at the serine metabolism gene PHGDH

Efficient interventions to reduce blood triglycerides are few; newer and more tolerable intervention targets are needed. Understanding the molecular mechanisms underlying blood triglyceride levels variation is key to identifying new therapies. To explore the role of epigenetic mechanisms on triglyceride levels, a blood methylome scan was conducted in 199 individuals from 5 French-Canadian families ascertained on venous thromboembolism, and findings were replicated in 324 French unrelated patients with venous thromboembolism. Genetic context and functional relevance were investigated. Two DNA methylation sites associated with triglyceride levels were identified. The first one, located in the ABCG1 gene, was recently reported, whereas the second one, located in the promoter of the PHGDH gene, is novel. The PHGDH methylation site, cg14476101, was found to be associated with variation in triglyceride levels in a threshold manner: cg14476101 was inversely associated with triglyceride levels only when triglyceride levels were above 1.12 mmol/L (discovery P-value = 8.4 × 10-6; replication P-value = 0.0091). Public databases findings supported a functional role of cg14476101 on PHGDH expression. PHGDH catalyses the first step in the serine biosynthesis pathway. These findings highlight the role of epigenetic regulation of the PHGDH gene in triglyceride metabolism, providing novel insights on putative intervention targets.