Intestine specific deletion of acyl co a monoacylglycerol acyltransferase

Intestine specific deletion of Acyl CoA monoacylglycerol Acyltransferase (MGAT)2 protects Mice from Diet-

Induced Obesity and Glucose Intolerance

May 1, 2014., Journal of Biological Sciences

Yeshwanthi SinghDST INSPIRE-JRF

Lipid Science Department

• In Enterocyte: Re-esterification to form TAG.

• MGAT2 is expressed in tissues besides intestine, including adipose in both mice and humans

• MGAT2 (Mogat2–/–) are protected from dietinduced

obesity.• Mogat2–/– Mice had normal

amounts of dietary fat but increase their energy expenditure.

2

Introduction

Hypothesis

Intestinal MGAT2 regulatessystemic energy balance,

Objectives:

• To generate and characterize mice deficient in MGAT2 specifically in the small intestine (Mogat2IKO)

• To demonstrate Mogat2IKO mice and Mogat2–/– mice level of energy expenditure

• To check whether/not Mogat2IKO protected against diet induced weight gain and associated comorbidities, including hepatic steatosis, hypercholesterolemia, and glucose intolerance

Experimental work plan:

• Mice: mice with an intestine specific deletion of Mogat2 (Mogat2IKO mice) were produced.

• Genotyping: four primers were used,genotypes determined by PCR

• Diets: A series of semipurified (defined) diets containing 10, 45, or 60% calories from fat (D12450B, D12451, and D12492, Research Diets, New Brunswick, NJ)

Experimental work plan:

• Real-time quantitative PCR analysis: To assess the levels of Mogat2 mRNA

• In vitro monoacylglycerol-O-acyltransferase assays• Monoacylglycerol uptake and processing in

the small intestine• Spatial and temporal distribution of fat

absorption in the intestine

Experimental work plan:

• Metabolic phenotyping studies• Body weight response to chow or high-fat Feeding• Biochemical assays• Glucose metabolism• Statistical analyses

RESULTS

Result:1Generation of intestine-specific MGAT2 deficient mice.

Result:1Generation of intestine-specific MGAT2 deficient mice.

Result:2Intestine-specific inactivation of MGAT2 inhibits monoacylglycerol uptake and esterification, alters distribution of fat

Result:2Intestine-specific inactivation of MGAT2 inhibits monoacylglycerol uptake and esterification, alters distribution of fat

Result:3 Inactivation of intestinal MGAT2 increases postprandial plasma GLP-1.

Result:4Intestine-specific inactivation of MGAT2 protects against excessive weight gain inducedby diets.

Result:4Intestine-specific inactivation of MGAT2 protects against excessive weight gain inducedby diets.

Result:5 Inactivation of intestinal MGAT2 alters energy balance..

Result:5 Inactivation of intestinal MGAT2 alters energy balance..

Result:6Intestine-specific inactivation of MGAT2 protects mice against hepatic steatosis inducedby high-fat feeding.

Result:6Intestine-specific inactivation of MGAT2 protects mice against hepatic steatosis inducedby high-fat feeding.

Result:7Intestine-specific inactivation of MGAT2 protects mice from impaired glucosemetabolism following high-fat feeding.

Result:7Intestine-specific inactivation of MGAT2 protects mice from impaired glucosemetabolism following high-fat feeding.

Conclusion

• Generated and characterized mice lacking MGAT2 specifically in the intestine

• Although the protection is not to the same extent as with global deletion of MGAT2

• Deficiency of intestinal MGAT2 was sufficient to deter excess fat accumulation resulting from highfat feeding

• Thus MGAT2 is the feasible target for excess calorie uptake and storage

Future Directions

• MGAT3, a homolog of MGAT2, is also expressed in human intestine

As MGAT3 is not expressed in mice, whether MGAT3 could compensate fully for MGAT2 in

humans remains to be determined