Lysosomal acid lipase (LAL), encoded by the LIPA gene, is the key lysosomal hydrolase that cleaves cholesteryl esters (CE) and triglycerides (TG). Loss-of-function (LOF) mutations in LIPA result in cholesteryl ester storage disease (CESD), which manifests with hyperlipidemia, hepatic and macrophage CE accumulation, and atherosclerosis. Recently, genome-wide association studies (GWASs) identified LIPA as a novel locus for coronary artery disease (CAD). Surprisingly, LIPA CAD-GWAS risk alleles do not associate with altered plasma lipids or hepatic LIPA mRNA levels but actually relate to higher monocyte LIPA mRNA expression. Our preliminary data also reveal a coincident increase in both LIPA mRNA and LAL enzymatic activity in monocyte-derived macrophages (HMDM) of CAD risk allele carriers, suggesting that monocyte/macrophage-specific gain-of-function (GOF) of LIPA may explain the GWAS CAD risk alleles. LIPA mRNA and LAL activity were markedly induced upon HMDM differentiation and mature HMDM secrets LAL. Extracellular LAL is abundant in the neointima of advanced human atherosclerotic lesions where LAL can remain enzymatically active in the lesion acidic microenvironment. Thus, macrophage LIPA GOF may aggravate atherosclerosis through accelerating intracellular LAL-induced lysosomal free cholesterol (FC) toxicity and extracellular LAL actions on low-density lipoprotein (LDL). My working hypotheses are that LIPA CAD risk alleles encode for macrophage-specific LIPA GOF, and therefore CAD risk alleles or macrophage LIPA overexpression will (i) increase intracellular LAL activity resulting in a shift toward greater lysosomal CE hydrolysis and FC accumulation and thus accelerate macrophage lysosomal dysfunction during modified-LDL loading; (ii) increase macrophage LAL secretion and extracellular LAL-mediated LDL modification driving atherogenic phenotypes in vascular smooth muscle cells (VSMC) and endothelial cells (EC); and (iii) macrophage LIPA overexpression will accelerate atherogenesis in ApoE-/- and Ldlr-/- mice. These hypotheses will be addressed in primary HMDM of specific LIPA genotype, through causal modeling in a novel human iPSC- differentiated macrophage (IPSDM) system utilizing CRISPR/Cas knock-in of risk alleles, in HMDM with lentivirus-mediated LIPA overexpression (Lenti-LIPA), and in murine models with macrophage-specific Lipa overexpression by lentivirus-infected bone marrow (BM) transplantation driven by macrophage-specific promoter. These will be accomplished by pursuing the following three aims:
Aim 1. K99 Phase: Determine the effects of LIPA CAD risk alleles and LIPA overexpression on intracellular macrophage LIPA expression, LAL activity, and phenotype of human macrophages.
Aim 2. R00 Phase: Determine the effects of LIPA CAD risk alleles and LIPA overexpression on macrophage LAL secretion, extracellular LAL-modification of LDL and on atherogenic phenotypes in EC and VSMC.
Aim 3. R00 Phase: Determine if macrophage Lipa overexpression accelerates atherosclerosis in ApoE-/- and Ldlr-/- mice.

Public Health Relevance

Recent genome-wide association studies (GWAS) identified lysosomal acid lipase (LIPA) as a susceptibility gene for coronary artery disease (CAD). The research outlined in this proposal has broad significance for better understanding of the novel mechanisms of GWAS CAD-associated LIPA in atherosclerosis, and in translational research exploring the therapeutic opportunities to prevent and treat CAD.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Career Transition Award (K99)
Project #
Application #
Study Section
Special Emphasis Panel (MTI (OA))
Program Officer
Carlson, Drew E
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Columbia University (N.Y.)
Internal Medicine/Medicine
Schools of Medicine
New York
United States
Zip Code
Shah, Rachana D; Xue, Chenyi; Zhang, Hanrui et al. (2017) Expression of Calgranulin Genes S100A8, S100A9 and S100A12 Is Modulated by n-3 PUFA during Inflammation in Adipose Tissue and Mononuclear Cells. PLoS One 12:e0169614
Zhang, Hanrui; Shi, Jianting; Hachet, Melanie A et al. (2017) CRISPR/Cas9-Mediated Gene Editing in Human iPSC-Derived Macrophage Reveals Lysosomal Acid Lipase Function in Human Macrophages-Brief Report. Arterioscler Thromb Vasc Biol 37:2156-2160
Zhang, Hanrui; Reilly, Muredach P (2017) LIPA Variants in Genome-Wide Association Studies of Coronary Artery Diseases: Loss-of-Function or Gain-of-Function? Arterioscler Thromb Vasc Biol 37:1015-1017
Zhang, Hanrui; Reilly, Muredach P (2017) Human Induced Pluripotent Stem Cell-Derived Macrophages for Unraveling Human Macrophage Biology. Arterioscler Thromb Vasc Biol 37:2000-2006
Zhang, Hanrui; Hinkle, Christine C; O'Neill, Sean M et al. (2017) Synergistic Modulation of Inflammatory but not Metabolic Effects of High-Fat Feeding by CCR2 and CX3CR1. Obesity (Silver Spring) 25:1410-1420
Xue, Chenyi; Zhang, Xuan; Zhang, Hanrui et al. (2017) De novo RNA sequence assembly during in vivo inflammatory stress reveals hundreds of unannotated lincRNAs in human blood CD14+ monocytes and in adipose tissue. Physiol Genomics 49:287-305