# Dysfunctional adipose tissue's role in hepatic metabolic disease

> **NIH NIH P20** · UNIVERSITY OF KANSAS MEDICAL CENTER · 2024 · $234,811

## Abstract

Excess adipose tissue (obesity) has been identified as a leading risk factor for developing fatty liver disease and 
type 2 diabetes. Paradoxically, the marked absence of adipose tissue (lipodystrophy) also leads to these 
comorbidities. These observations suggest that adipose function, not quantity, is critical for systemic metabolic 
regulation. The primary function of healthy adipose tissue is the regulated storage of lipids when nutrients are 
abundant and mobilization of free fatty acids and glycerol when nutrients are scarce, but dysfunction of these 
processes leads to ectopic lipid storage in the liver, which drives metabolic disease. Dogma suggests excessive 
free fatty acid export from visceral adipose dumps into the portal vein, overwhelming hepatic metabolism leading 
to hepatic steatosis. Obese patients have a reduced capacity to store fatty acids in adipose tissue and 
dysregulated lipolysis. However, recent studies suggest that ~40 % of hepatic lipids are derived by hepatic de 
novo lipogenesis (DNL), the conversion of carbohydrates to lipids within the liver. Hepatic DNL is regulated by 
the nutrient-sensing AMP Protein Kinase (AMPK), which suppresses the activity and expression of many DNL 
enzymes. The goal of this 3-year project is to establish the mechanistic links between adipose tissue dysfunction 
and dysregulated hepatic DNL. In adipocytes, triglycerides are generated through the glycerol-3-phosphate 
pathway. The penultimate step is the generation of diacylglycerol through the phosphatidic acid 
phosphohydrolase activity of lipin 1 (gene name Lpin1). Our preliminary data shows that in humans adipose, 
LPIN1 expression positively correlates with insulin sensitivity and negatively corelates to hepatic DNL. In line 
with this, we have generated mice lacking lipin 1 in adipose tissue, which display a lean, yet metabolically 
unhealthy phenotype that includes hepatic steatosis and insulin resistance. Importantly, these mice also have 
increased rates of hepatic DNL and expression of DNL enzymes that AMPK normally suppresses. Together 
these data suggest that inhibiting adipose tissue triglyceride synthesis activates de novo hepatic lipid synthesis 
from alternative carbon sources. We hypothesize that dysfunctional adipose tissue reduces hepatic nutrient 
sensing capacity through chronic AMPK inactivation driving DNL and hepatic steatosis. We also hypothesize 
that re-activation of hepatic AMPK will restore hepatic nutrient sensing serving to lower DNL and hepatic lipid 
storage. Because obesity is an acquired disease, we will use a model of adult-onset adipose dysfunction, an 
inducible adipose specific lipin 1 KO model. We will use comprehensive metabolic testing combined with 
phospho-proteomics to assess AMPK activation of hepatic DNL. We will overexpress constitutively active AMPK 
in livers of our adipose dysfunction models to rescue hepatic metabolism by suppressing DNL. We will also use 
multi-organ biopsies from the sa...

## Key facts

- **NIH application ID:** 11013540
- **Project number:** 5P20GM144269-03
- **Recipient organization:** UNIVERSITY OF KANSAS MEDICAL CENTER
- **Principal Investigator:** Andrew Lutkewitte
- **Activity code:** P20 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $234,811
- **Award type:** 5
- **Project period:** 2022-04-01 → 2027-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11013540

## Citation

> US National Institutes of Health, RePORTER application 11013540, Dysfunctional adipose tissue's role in hepatic metabolic disease (5P20GM144269-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/11013540. Licensed CC0.

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