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1.  Lipin-1 flexes its muscle in autophagy 
Cell Cycle  2014;13(24):3789-3790.
PMCID: PMC4615126  PMID: 25483058
2.  Lipin-1 Regulates Autophagy Clearance and Intersects with Statin Drug Effects in Skeletal Muscle 
Cell metabolism  2014;20(2):267-279.
LPIN1 encodes lipin-1, a phosphatidic acid phosphatase (PAP) enzyme that catalyzes the dephosphorylation of phosphatidic acid to form diacylglycerol. Homozygous LPIN1 gene mutations cause severe rhabdomyolysis, and heterozygous LPIN1 missense mutations may promote statin-induced myopathy. We demonstrate that lipin-1–related myopathy in the mouse is associated with a blockade in autophagic flux and accumulation of aberrant mitochondria. Lipin-1 PAP activity is required for maturation of autolysosomes, through its activation of the protein kinase D (PKD)-Vps34 phosphatidylinositol 3-kinase signaling cascade. Statin treatment also reduces PKD activation and autophagic flux, which are compounded by diminished mTOR abundance in lipin-1-haploinsufficent and –deficient muscle. Lipin-1 restoration in skeletal muscle prevents myonecrosis and statin toxicity in vivo, and activated protein kinase D rescues autophagic flux and lipid homeostasis in lipin-1–deficient cells. Our findings identify lipin-1 PAP activity as a component of the macroautophagy pathway, and define the basis for lipin-1–related myopathies.
PMCID: PMC4170588  PMID: 24930972
3.  The lipin protein family: dual roles in lipid biosynthesis and gene expression 
FEBS letters  2007;582(1):90-96.
The prevalence of obesity in the western world has focused attention on factors that influence triglyceride biosynthesis, storage, and utilization. Members of the lipin protein family have a newly discovered enzymatic role in triglyceride and phospholipid biosynthesis as a phosphatidate phosphatase, and also act as an inducible transcriptional coactivator in conjunction with PGC-1α and PPARα. Through these activities, the founding member of the family, lipin-1, influences lipid metabolism and glucose homeostasis in diverse tissues including adipose tissue, skeletal muscle, and liver. The physiological roles of lipin-2 and lipin-3 are less well defined, but are likely to carry out similar functions in glycerolipid biosynthesis and gene expression in a distinct tissue distribution.
PMCID: PMC2848953  PMID: 18023282
adipose tissue; ipodystrophy; obesity; triaclyglycerol; phosphatidate phosphatase; transcriptional coactivator
4.  Adipose tissue dysfunction tracks disease progression in two Huntington's disease mouse models 
Human Molecular Genetics  2009;18(6):1006-1016.
In addition to the hallmark neurological manifestations of Huntington's disease (HD), weight loss with metabolic dysfunction is often observed in the later stages of disease progression and is associated with poor prognosis. The mechanism for weight loss in HD is unknown. Using two mouse models of HD, the R6/2 transgenic and CAG140 knock-in mouse strains, we demonstrate that adipose tissue dysfunction is detectable at early ages and becomes more pronounced as the disease progresses. Adipocytes acquire a ‘de-differentiated’ phenotype characterized by impaired expression of fat storage genes. In addition, HD mice exhibit reduced levels of leptin and adiponectin, adipose tissue-derived hormones that regulate food intake and glucose metabolism. Importantly, some of these changes occur prior to weight loss and development of some of the characteristic neurological symptoms. We demonstrate that impaired gene expression and lipid accumulation in adipocytes can be recapitulated by expression of an inducible mutant huntingtin transgene in an adipocyte cell line and that mutant huntingtin inhibits transcriptional activity of the PGC-1α co-activator in adipocytes, which may contribute to aberrant gene expression. Thus, our findings indicate that mutant huntingtin has direct detrimental effects in cell types other than neurons. The results also indicate that circulating adipose-tissue-derived hormones may be accessible markers for HD prognosis and progression and suggest that adipose tissue may be a useful therapeutic target to improve standard of life for HD patients.
PMCID: PMC2649017  PMID: 19124532
5.  PGC-1α Inhibits Oleic Acid Induced Proliferation and Migration of Rat Vascular Smooth Muscle Cells 
PLoS ONE  2007;2(11):e1137.
Oleic acid (OA) stimulates vascular smooth muscle cell (VSMC) proliferation and migration. The precise mechanism is still unclear. We sought to investigate the effects of peroxisome proliferator-activated receptor gamma (PPARγ) coactivator-1 alpha (PGC-1α) on OA-induced VSMC proliferation and migration.
Principal Findings
Oleate and palmitate, the most abundant monounsaturated fatty acid and saturated fatty acid in plasma, respectively, differently affect the mRNA and protein levels of PGC-1α in VSMCs. OA treatment resulted in a reduction of PGC-1α expression, which may be responsible for the increase in VSMC proliferation and migration caused by this fatty acid. In fact, overexpression of PGC-1α prevented OA-induced VSMC proliferation and migration while suppression of PGC-1α by siRNA enhanced the effects of OA. In contrast, palmitic acid (PA) treatment led to opposite effects. This saturated fatty acid induced PGC-1α expression and prevented OA-induced VSMC proliferation and migration. Mechanistic study demonstrated that the effects of PGC-1α on VSMC proliferation and migration result from its capacity to prevent ERK phosphorylation.
OA and PA regulate PGC-1α expression in VSMCs differentially. OA stimulates VSMC proliferation and migration via suppression of PGC-1α expression while PA reverses the effects of OA by inducing PGC-1α expression. Upregulation of PGC-1α in VSMCs provides a potential novel strategy in preventing atherosclerosis.
PMCID: PMC2043491  PMID: 17987121

Results 1-5 (5)