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Jiang S, Ren Z, Yang Y, Liu Q, Zhou S, Xiao Y. The GPIHBP1-LPL complex and its role in plasma triglyceride metabolism: Insights into chylomicronemia. Biomed Pharmacother 2023; 169:115874. [PMID: 37951027 DOI: 10.1016/j.biopha.2023.115874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/06/2023] [Accepted: 11/07/2023] [Indexed: 11/13/2023] Open
Abstract
GPIHBP1 is a protein found in the endothelial cells of capillaries that is anchored by glycosylphosphatidylinositol and binds to high-density lipoproteins. GPIHBP1 attaches to lipoprotein lipase (LPL), subsequently carrying the enzyme and anchoring it to the capillary lumen. Enabling lipid metabolism is essential for the marginalization of lipoproteins alongside capillaries. Studies underscore the significance of GPIHBP1 in transporting, stabilizing, and aiding in the marginalization of LPL. The intricate interplay between GPIHBP1 and LPL has provided novel insights into chylomicronemia in recent years. Mutations hindering the formation or reducing the efficiency of the GPIHBP1-LPL complex are central to the onset of chylomicronemia. This review delves into the structural nuances of the GPIHBP1-LPL interaction, the consequences of mutations in the complex leading to chylomicronemia, and cutting-edge advancements in chylomicronemia treatment.
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Affiliation(s)
- Shali Jiang
- Department of Cardiovascular Medicine, Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, PR China; Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Zhuoqun Ren
- Department of Cardiovascular Medicine, Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, PR China; Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Yutao Yang
- Department of Cardiovascular Medicine, Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, PR China; Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, PR China
| | - Qiming Liu
- Department of Cardiovascular Medicine, Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, PR China
| | - Shenghua Zhou
- Department of Cardiovascular Medicine, Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, PR China
| | - Yichao Xiao
- Department of Cardiovascular Medicine, Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, PR China.
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Wu H, Xu H, Lei S, Yang Z, Yang S, Du J, Zhou Y, Liu Y, Yang Y, Hu Z. Loss-of-Function Homozygous Variant in LPL Causes Type I Hyperlipoproteinemia and Renal Lipidosis. Kidney Int Rep 2023; 8:2428-2438. [PMID: 38025240 PMCID: PMC10658268 DOI: 10.1016/j.ekir.2023.08.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 08/05/2023] [Accepted: 08/22/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Lipoprotein lipase (LPL) is an important enzyme in lipid metabolism, individuals with LPL gene variants could present type I hyperlipoproteinemia, lipemia retinalis, hepatosplenomegaly, and pancreatitis. To date, there are no reports of renal lipidosis induced by type I hyperlipoproteinemia due to LPL mutation. Methods Renal biopsy was conducted to confirm the etiological factor of nephrotic syndrome in a 44-year-old Chinese man. Lipoprotein electrophoresis, apoE genotype detection, and whole-exome sequencing were performed to confirm the dyslipidemia type and genetic factor. Analysis of the 3-dimensional protein structure and in vitro functional study were conducted to verify variant pathogenicity. Results Renal biopsy revealed numerous CD68 positive foam cells infiltrated in the glomeruli; immunoglobulin and complement staining were negative; and electron microscopy revealed numerous lipid droplets and cholesterol clefts in the cytoplasm of foam cells. Lipoprotein electrophoresis revealed that the patient fulfilled the diagnostic criteria of type I hyperlipoproteinemia. The apoE genotype of the patient was the ε3/ε3 genotype. Whole-exome sequencing revealed an LPL (c.292G > A, p.A98T) homozygous variant with α-helix instability and reduced post-heparin LPL activity but normal lipid uptake capability compared to the wild-type variant. Conclusion LPL (c.292G > A, p.A98T) is a pathogenic variant that causes renal lipidosis associated with type I hyperlipoproteinemia. This study provides adequate evidence of the causal relationship between dyslipidemia and renal lesions. However, further research is needed to better understand the pathogenetic mechanism of LPL variant-related renal lesions.
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Affiliation(s)
- Hongyan Wu
- Department of Nephrology, West China Hospital, Sichuan University, Chengdu, China
| | - Huan Xu
- Department of Pathology, West China Hospital, Sichuan University, Chengdu, China
| | - Song Lei
- Department of Pathology, West China Hospital, Sichuan University, Chengdu, China
| | - Zhi Yang
- Department of Nephrology, West China Hospital, Sichuan University, Chengdu, China
| | - Shan Yang
- Department of Nephrology, West China Hospital, Sichuan University, Chengdu, China
| | - Jingxue Du
- Department of Nephrology, West China Hospital, Sichuan University, Chengdu, China
| | - Yi Zhou
- Department of Nephrology, West China Hospital, Sichuan University, Chengdu, China
| | - Yunqiang Liu
- Department of Medical Genetics, West China Hospital, Sichuan University, Chengdu, China
| | - Yuan Yang
- Department of Medical Genetics, West China Hospital, Sichuan University, Chengdu, China
| | - Zhangxue Hu
- Department of Nephrology, West China Hospital, Sichuan University, Chengdu, China
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Camacho A, Ariza MJ, Amigó N, Macías Guillén P, Sánchez Chaparro MÁ, Valdivielso P. A case of hypocholesterolemia under study. CLINICA E INVESTIGACION EN ARTERIOSCLEROSIS : PUBLICACION OFICIAL DE LA SOCIEDAD ESPANOLA DE ARTERIOSCLEROSIS 2023; 35:244-247. [PMID: 37302939 DOI: 10.1016/j.arteri.2023.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 05/16/2023] [Indexed: 06/13/2023]
Abstract
Primary hypocholesterolemia (or hypobetalipoproteinemia) is a rare disorder of lipoprotein metabolism that may be due to a polygenic predisposition or a monogenic disease. Among these, it is possible to differentiate between symptomatic and asymptomatic forms, in which, in the absence of secondary causes, the initial clinical suspicion is plasma ApoB levels below the 5th percentile of the distribution by age and sex. Here we describe the differential diagnosis of a case of asymptomatic hypocholesterolemia. We studied proband's clinical data, the lipid profile of the proband and her relatives and the clinical data of the family relevant to carry out the differential diagnosis. We performed a genetic study as the diagnostic test. The information obtained from the differential diagnosis suggested a heterozygous hypobetalipoproteinemia due to PCSK9 loss-of-function variants. The diagnostic test revealed, in the proband, the presence of a heterozygous PCSK9 frame-shift variant of a maternal origin. Plasma levels of LDL cholesterol and PCSK9 of the patient and her relatives were compatible with the segregation of the variant revealed. In conclusion, the diagnostic test performed confirmed the suspected diagnosis of the proband as asymptomatic familial hypobetalipoproteinemia due to a loss-of-function variant in the PCSK9 gene.
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Affiliation(s)
- Ana Camacho
- Servicio de Medicina Interna, Hospital Infanta-Elena, Huelva, España
| | - María José Ariza
- Laboratorio de Lípidos y Arteriosclerosis, Departamento de Medicina y Dermatología, Centro de Investigaciones Médico Sanitarias (CIMES), Instituto de Investigación Biomédica de Málaga (IBIMA-Plataforma Bionand), Universidad de Málaga, Málaga, España.
| | - Nuria Amigó
- Biosfer Teslab Metabolomics Interdisciplinary Laboratory, Instituto de Investigación Sanitaria Pere Virgili (IISPV) , Reus, Tarragona, España; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, España
| | - Patricia Macías Guillén
- Laboratorio de Lípidos y Arteriosclerosis, Departamento de Medicina y Dermatología, Centro de Investigaciones Médico Sanitarias (CIMES), Instituto de Investigación Biomédica de Málaga (IBIMA-Plataforma Bionand), Universidad de Málaga, Málaga, España
| | - Miguel Ángel Sánchez Chaparro
- Laboratorio de Lípidos y Arteriosclerosis, Departamento de Medicina y Dermatología, Centro de Investigaciones Médico Sanitarias (CIMES), Instituto de Investigación Biomédica de Málaga (IBIMA-Plataforma Bionand), Universidad de Málaga, Málaga, España; Servicio de Medicina Interna, Hospital Universitario Virgen de la Victoria, Málaga, España
| | - Pedro Valdivielso
- Laboratorio de Lípidos y Arteriosclerosis, Departamento de Medicina y Dermatología, Centro de Investigaciones Médico Sanitarias (CIMES), Instituto de Investigación Biomédica de Málaga (IBIMA-Plataforma Bionand), Universidad de Málaga, Málaga, España; Servicio de Medicina Interna, Hospital Universitario Virgen de la Victoria, Málaga, España
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Feng L, Sun Y, Liu F, Wang C, Zhang C, Liu J, Jiang L. Clinical features and functions of a novel Lpl mutation C.986A>C (p.Y329S) in patient with hypertriglyceridemia. Curr Res Transl Med 2022; 70:103337. [PMID: 35679768 DOI: 10.1016/j.retram.2022.103337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 12/11/2021] [Accepted: 02/08/2022] [Indexed: 01/31/2023]
Abstract
OBJECTIVE To investigate and assess the clinical features and functions of a new lipoprotein lipase (Lpl) gene mutation c.986A>C (p.Y329S) found in hypertriglyceridemia(HTG) patients from a Chinese family. METHODS Five members of a family with the proband were diagnosed with HTG were investigated, and fasting peripheral blood was collected . The plasma was then used to measure triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein cholesterol (HDL-C), free fatty acids (FFA), and glucose tolerance. Following that, genomic deoxyribonucleic acid (DNA) was extracted from whole-blood samples using the QIAamp whole-blood DNA kit, and the coding exon regions and flanking regions of 95 dyslipidemia-related genes were captured using GenCap liquid-phase target gene capture technology. The activity of LPL and its mutation were then determined using cell assays, and the newly discovered LPL mutant was functionally analyzed. The binding site of fenofibrate and LPL, as well as the mutation, were subjected to predictive analysis. RESULTS The LPL gene's c.986A>C (p.Y329S) heterozygous mutation was discovered, and patients with the mutation had the typical phenotype of LPL deficiency and weakened LPL activity. Furthermore, this mutant has been treated with fenofibrate, and its triglyceride level is perfectly controlled and stable. The prediction analysis of the fenofibrate and LPL binding sites reveals that the wild-type system, Phe378 contributes most to the binding energy of fenofibrate. In the mutant system, Tyr394, which contributes the most to the binding energy of fenofibrate, the contribution of S329 is greater than that of Y329 (0.9∼0.7 kal/mol) . After Y329 is mutated, the hydrogen bond data of fenofibrate and LPL will also increase to quote H-bond diagrams. CONCLUSIONS A heterozygous mutation c.986A>C (p.Y329S) in exon 6 of Lpl gene occurs in the proband with familial HTG. Lpl c.986A>C (p.Y329S) mutation weakens the activity of the LPL, which may be the pathogenic mutation of HTG. In addition, The proband has been treated with fenofibrate and the triglyceride level is ideally controlled and stable. The prediction analysis of the fenofibrate and LPL binding site shows that the wild-type system, Phe378 contributes most to the binding energy of fenofibrate. In the mutant system, Tyr394, which contributes the most to the binding energy of fenofibrate, the contribution of S329 is greater than that of Y329 (0.9∼0.7 kal/mol). After Y329 is mutated, the hydrogen bond data of fenofibrate and LPL will also increase, which may be one of the reasons why the mutation has no effect on the therapeutic effect of fenofibrate.
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Affiliation(s)
- Lingling Feng
- Department of Endocrinology, Qilu Hospital, Cheeloo college of medicine, Shandong University, Jinan, 250012, China; Department of Endocrinology, Laoling People's Hospital, Laoling 253600, Shandong Province, China
| | - Yujing Sun
- Department of Endocrinology, Qilu Hospital, Cheeloo college of medicine, Shandong University, Jinan, 250012, China; Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, 250012, Shandong Province, China; Jinan Clinical Research Center for Endocrine and Metabolic Diseases, Jinan, 250012, Shandong Province, China
| | - Fuqiang Liu
- Department of Endocrinology, Qilu Hospital, Cheeloo college of medicine, Shandong University, Jinan, 250012, China; Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, 250012, Shandong Province, China; Jinan Clinical Research Center for Endocrine and Metabolic Diseases, Jinan, 250012, Shandong Province, China
| | - Chuan Wang
- Department of Endocrinology, Qilu Hospital, Cheeloo college of medicine, Shandong University, Jinan, 250012, China; Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, 250012, Shandong Province, China; Jinan Clinical Research Center for Endocrine and Metabolic Diseases, Jinan, 250012, Shandong Province, China
| | - Chao Zhang
- Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, Shandong, 250012, China
| | - Jidong Liu
- Department of Endocrinology, Qilu Hospital, Cheeloo college of medicine, Shandong University, Jinan, 250012, China; Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, 250012, Shandong Province, China; Jinan Clinical Research Center for Endocrine and Metabolic Diseases, Jinan, 250012, Shandong Province, China
| | - Ling Jiang
- Department of Endocrinology, Qilu Hospital, Cheeloo college of medicine, Shandong University, Jinan, 250012, China; Institute of Endocrine and Metabolic Diseases of Shandong University, Jinan, 250012, Shandong Province, China; Jinan Clinical Research Center for Endocrine and Metabolic Diseases, Jinan, 250012, Shandong Province, China.
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Kardassis D, Thymiakou E, Chroni A. Genetics and regulation of HDL metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1867:159060. [PMID: 34624513 DOI: 10.1016/j.bbalip.2021.159060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 09/06/2021] [Accepted: 09/09/2021] [Indexed: 02/07/2023]
Abstract
The inverse association between plasma HDL cholesterol (HDL-C) levels and risk for cardiovascular disease (CVD) has been demonstrated by numerous epidemiological studies. However, efforts to reduce CVD risk by pharmaceutically manipulating HDL-C levels failed and refused the HDL hypothesis. HDL-C levels in the general population are highly heterogeneous and are determined by a combination of genetic and environmental factors. Insights into the causes of HDL-C heterogeneity came from the study of monogenic HDL deficiency syndromes but also from genome wide association and Μendelian randomization studies which revealed the contribution of a large number of loci to low or high HDL-C cases in the general or in restricted ethnic populations. Furthermore, HDL-C levels in the plasma are under the control of transcription factor families acting primarily in the liver including members of the hormone nuclear receptors (PPARs, LXRs, HNF-4) and forkhead box proteins (FOXO1-4) and activating transcription factors (ATFs). The effects of certain lipid lowering drugs used today are based on the modulation of the activity of specific members of these transcription factors. During the past decade, the roles of small or long non-coding RNAs acting post-transcriptionally on the expression of HDL genes have emerged and provided novel insights into HDL regulation and new opportunities for therapeutic interventions. In the present review we summarize recent progress made in the genetics and the regulation (transcriptional and post-transcriptional) of HDL metabolism.
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Affiliation(s)
- Dimitris Kardassis
- Laboratory of Biochemistry, Department of Basic Sciences, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology of Hellas, Heraklion, Greece.
| | - Efstathia Thymiakou
- Laboratory of Biochemistry, Department of Basic Sciences, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology of Hellas, Heraklion, Greece
| | - Angeliki Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Agia Paraskevi, Athens, Greece
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Duplex high resolution melting analysis (dHRMA) to detect two hot spot CYP24A1 pathogenic variants (PVs) associated to idiopathic infantile hypercalcemia (IIH). Mol Biol Rep 2021; 48:3303-3311. [PMID: 33864587 PMCID: PMC8172411 DOI: 10.1007/s11033-021-06324-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 03/27/2021] [Indexed: 11/06/2022]
Abstract
Pathogenic variants (PVs) in CYP24A1 gene are associated with Idiopathic Infantile Hypercalcemia disease (IIH). The identification of CYP24A1 PVs can be a useful tool for the improvement of target therapeutic strategies. Aim of this study is to set up a rapid and inexpensive High Resolution Melting Analysis (HRMA)-based method for the simultaneous genotyping of two hot spot PVs in CYP24A1 gene, involved in IIH. A duplex-HRMA (dHRMA) was designed in order to detect simultaneously CYP24A1 c.428_430delAAG, p.(Glu143del) (rs777676129) and c.1186C > T, p.(Arg396Trp) (rs114368325), in peculiar cases addressed to our Laboratory. dHRMA was able to identify clearly and simultaneously both hot spot CYP24A1 PVs evaluating melting curve shape and melting temperature (Tm). This is the first dHRMA approach to rapidly screen the two most frequent CYP24A1 PVs in peculiar case, providing useful information for diagnosis and patient management in IIH disease.
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A novel GPIHBP1 mutation related to familial chylomicronemia syndrome: A series of cases. Atherosclerosis 2021; 322:31-38. [PMID: 33706081 DOI: 10.1016/j.atherosclerosis.2021.02.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 02/10/2021] [Accepted: 02/18/2021] [Indexed: 01/13/2023]
Abstract
BACKGROUND AND AIMS GPIHBP1 is an accessory protein of lipoprotein lipase (LPL) essential for its functioning. Mutations in the GPIHBP1 gene cause a deficit in the action of LPL, leading to severe hypertriglyceridemia and increased risk for acute pancreatitis. METHODS We describe twelve patients (nine women) with a novel homozygous mutation in intron 2 of the GPIHBP1 gene. RESULTS All patients were from the Northeastern region of Brazil and presented the same homozygous variant located in a highly conserved 3' splicing acceptor site of the GPIHBP1 gene. This new variant was named c.182-1G > T, according to HGVS recommendations. We verified this new GPIHBP1 variant's effect by using the Human Splicing Finder (HSF) tool. This mutation changes the GPIHBP1 pre-mRNA processing and possibly causes the skipping of the exon 3 of the GPIHBP1 gene, affecting almost 50% of the cysteine-rich Lys6 GPIHBP1 domain. Patients presented with severe hypertriglyceridemia (2351 mg/dl [885-20600]) and low HDL (18 mg/dl [5-41). Four patients (33%) had a previous history of acute pancreatitis. CONCLUSIONS We describe a novel GPIHBP1 pathogenic intronic mutation of patients from the Northeast region of Brazil, suggesting the occurrence of a founder effect.
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