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Groenen AG, Matveyenko A, Matienzo N, Halmos B, Zhang H, Westerterp M, Reyes-Soffer G. Apolipoprotein(a) production and clearance are associated with plasma IL-6 and IL-18 levels, dependent on ethnicity. Atherosclerosis 2024; 391:117474. [PMID: 38428286 DOI: 10.1016/j.atherosclerosis.2024.117474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 03/03/2024]
Abstract
BACKGROUND AND AIMS High plasma lipoprotein (a) [Lp(a)] levels are associated with increased atherosclerotic cardiovascular disease (ASCVD), in part attributed to elevated inflammation. High plasma Lp(a) levels inversely correlate with apolipoprotein (a) [(APO(a)] isoform size. APO(a) isoform size is negatively associated with APO(a) production rate (PR) and positively associated with APO(a) fractional catabolic rate (FCR). We asked whether APO(a) PR and FCR (kinetics) are associated with plasma levels of interleukin (IL)-6 and IL-18, pro-inflammatory interleukins that promote ASCVD. METHODS We used samples from existing data of APO(a) kinetic studies from an ethnically diverse cohort (n = 25: 10 Black, 9 Hispanic, and 6 White subjects) and assessed IL-6 and IL-18 plasma levels. We performed multivariate linear regression analyses to examine the relationships between predictors APO(a) PR or APO(a) FCR, and outcome variables IL-6 or IL-18. In these analyses, we adjusted for parameters known to affect Lp(a) levels and APO(a) PR and FCR, including race/ethnicity and APO(a) isoform size. RESULTS APO(a) PR and FCR were positively associated with plasma IL-6, independent of isoform size, and dependent on race/ethnicity. APO(a) PR was positively associated with plasma IL-18, independent of isoform size and race/ethnicity. APO(a) FCR was not associated with plasma IL-18. CONCLUSIONS Our studies demonstrate a relationship between APO(a) PR and FCR and plasma IL-6 or IL-18, interleukins that promote ASCVD. These studies provide new insights into Lp(a) pro-inflammatory properties and are especially relevant in view of therapies targeting APO(a) to decrease cardiovascular risk.
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Affiliation(s)
- Anouk G Groenen
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Anastasiya Matveyenko
- Columbia University Irving Medical Center, College of Physicians and Surgeons, Department of Medicine, Division of Preventive Medicine and Nutrition, New York, NY, USA
| | - Nelsa Matienzo
- Columbia University Irving Medical Center, College of Physicians and Surgeons, Department of Medicine, Division of Preventive Medicine and Nutrition, New York, NY, USA
| | - Benedek Halmos
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Hanrui Zhang
- Columbia University Irving Medical Center, Division of Cardiology, New York, NY, USA
| | - Marit Westerterp
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
| | - Gissette Reyes-Soffer
- Columbia University Irving Medical Center, College of Physicians and Surgeons, Department of Medicine, Division of Preventive Medicine and Nutrition, New York, NY, USA.
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Matveyenko A, Seid H, Kim K, Ramakrishnan R, Thomas T, Matienzo N, Reyes-Soffer G. Association of free-living diet composition with plasma lipoprotein(a) levels in healthy adults. Lipids Health Dis 2023; 22:144. [PMID: 37670291 PMCID: PMC10478368 DOI: 10.1186/s12944-023-01884-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 07/27/2023] [Indexed: 09/07/2023] Open
Abstract
BACKGROUND Lipoprotein (a) [Lp(a)] is an apoB100-containing lipoprotein with high levels being positively associated with atherosclerotic cardiovascular disease. Lp(a) levels are genetically determined. However, previous studies report a negative association between Lp(a) and saturated fatty acid intake. Currently, apoB100 lowering therapies are used to lower Lp(a) levels, and apheresis therapy is FDA approved for patients with extreme elevations of Lp(a). The current study analyzed the association of free-living diet components with plasma Lp(a) levels. METHODS Dietary composition data was collected during screening visits for enrollment in previously completed lipid and lipoprotein metabolism studies at Columbia University Irving Medical Center via a standardized protocol by registered dietitians using 24 hour recalls. Data were analyzed with the Nutrition Data System for Research (Version 2018). Diet quality was calculated using the Healthy Eating Index (HEI) score. Fasting plasma Lp(a) levels were measured via an isoform-independent ELISA and apo(a) isoforms were measured using gel electrophoresis. RESULTS We enrolled 28 subjects [Black (n = 18); Hispanic (n = 7); White (n = 3)]. The mean age was 48.3 ± 12.5 years with 17 males. Median level of Lp(a) was 79.9 nmol/L (34.4-146.0) and it was negatively associated with absolute (grams/day) and relative (percent of total calories) intake of dietary saturated fatty acids (SFA) (R = -0.43, P = 0.02, SFA …(% CAL): R = -0.38, P = 0.04), palmitic acid intake (R = -0.38, P = 0.05), and stearic acid intake (R = -0.40, P = 0.03). Analyses of associations with HEI score when stratified based on Lp(a) levels > or ≤ 100 nmol/L revealed no significant associations with any of the constituent factors. CONCLUSIONS Using 24 hour recall, we confirm previous findings that Lp(a) levels are negatively associated with dietary saturated fatty acid intake. Additionally, Lp(a) levels are not related to diet quality, as assessed by the HEI score. The mechanisms underlying the relationship of SFA with Lp(a) require further investigation.
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Affiliation(s)
- Anastasiya Matveyenko
- Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, N.Y, USA
| | - Heather Seid
- Irving Institute for Clinical and Translational Research, Columbia University, New York, N.Y, USA
| | - Kyungyeon Kim
- Institute of Human Nutrition, Columbia University, New York, N.Y, USA
| | - Rajasekhar Ramakrishnan
- Center for Biomathematics, Department of Pediatrics, Columbia University Vagelos College of Physicians and Surgeons, New York, N.Y, USA
| | - Tiffany Thomas
- Department of Pathology and Cell Biology, Columbia University Vagelos College of Physicians and Surgeons, New York, N.Y, USA
| | - Nelsa Matienzo
- Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, N.Y, USA
| | - Gissette Reyes-Soffer
- Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, N.Y, USA.
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Reyes-Soffer G, Liu J, Thomas T, Matveyenko A, Seid H, Ramakrishnan R, Holleran S, Zaghloul N, Sztalryd-Woodle C, Pollin T, Ginsberg HN. TM6SF2 Determines Both the Degree of Lipidation and the Number of VLDL Particles Secreted by the Liver. medRxiv 2023:2023.06.23.23291823. [PMID: 37425717 PMCID: PMC10327233 DOI: 10.1101/2023.06.23.23291823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
In 2014, exome-wide studies identified a glutamine176lysine (p.E167K) substitution in a protein of unknown function named transmembrane 6 superfamily member 2 (TM6SF2). The p.E167K variant was associated with increased hepatic fat content and reduced levels of plasma TG and LDL cholesterol. Over the next several years, additional studies defined the role of TM6SF2, which resides in the ER and the ER-Golgi interface, in the lipidation of nascent VLDL to generate mature, more TG-rich VLDL. Consistent results from cells and rodents indicated that the secretion of TG was reduced in the p.E167K variant or when hepatic TM6SF2 was deleted. However, data for secretion of APOB was inconsistent, either reduced or increased secretion was observed. A recent study of people homozygous for the variant demonstrated reduced in vivo secretion of large, TG-rich VLDL1 into plasma; both TG and APOB secretion were reduced. Here we present new results demonstrating increased secretion of VLDL APOB with no change in TG secretion in p.E167K homozygous individuals from the Lancaster Amish community compared to their wild-type siblings. Our in vivo kinetic tracer results are supported by in vitro experiments in HepG2 and McA cells with knock-down or Crispr-deletions of TM6SF2, respectively. We offer a model to potentially explain all of the prior data and our new results.
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Matveyenko A, Pavlyha M, Reyes-Soffer G. Supporting evidence for lipoprotein(a) measurements in clinical practice. Best Pract Res Clin Endocrinol Metab 2023; 37:101746. [PMID: 36828715 PMCID: PMC11014458 DOI: 10.1016/j.beem.2023.101746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
High levels of lipoprotein(a) [Lp(a)] are causal for development of atherosclerotic cardiovascular disease and highly regulated by genetics. Levels are higher in Blacks compared to Whites, and in women compared to men. Lp(a)'s main protein components are apolipoprotein (apo) (a) and apoB100, the latter being the main component of Low-Density Lipoprotein (LDL) particles. Studies have identified Lp(a) to be associated with inflammatory, coagulation and wound healing pathways. Lack of validated and accepted assays to measure Lp(a), risk cutoff values, guidelines for diagnosis, and targeted therapies have added challenges to the field. Scientific efforts are ongoing to address these, including studies evaluating the cardiovascular benefits of decreasing Lp(a) levels with targeted apo(a) lowering treatments. This review will provide a synopsis of evidence-based effects of high Lp(a) on disease presentation, highlight available guidelines and discuss promising therapies in development. We will conclude with current clinical information and future research needs in the field.
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Affiliation(s)
- Anastasiya Matveyenko
- Columbia University College of Physicians and Surgeons, Columbia University Irving Medical Center, 622 West 168th Street, P&S 10-501, New York, NY 10032, USA.
| | - Marianna Pavlyha
- Columbia University College of Physicians and Surgeons, Columbia University Irving Medical Center, 622 West 168th Street, P&S 10-501, New York, NY 10032, USA.
| | - Gissette Reyes-Soffer
- Columbia University College of Physicians and Surgeons, Columbia University Irving Medical Center, 622 West 168th Street, P&S 10-501, New York, NY 10032, USA.
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Matveyenko A, Matienzo N, Ginsberg H, Nandakumar R, Seid H, Ramakrishnan R, Holleran S, Thomas T, Reyes-Soffer G. Relationship of apolipoprotein(a) isoform size with clearance and production of lipoprotein(a) in a diverse cohort. J Lipid Res 2023; 64:100336. [PMID: 36706955 PMCID: PMC10006688 DOI: 10.1016/j.jlr.2023.100336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 01/16/2023] [Accepted: 01/22/2023] [Indexed: 01/26/2023] Open
Abstract
Lipoprotein(a) [Lp(a)] has two main proteins, apoB100 and apo(a). High levels of Lp(a) confer an increased risk for atherosclerotic cardiovascular disease. Most people have two circulating isoforms of apo(a) differing in their molecular mass, determined by the number of Kringle IV Type 2 repeats. Previous studies report a strong inverse relationship between Lp(a) levels and apo(a) isoform sizes. The roles of Lp(a) production and fractional clearance and how ancestry affects this relationship remain incompletely defined. We therefore examined the relationships of apo(a) size with Lp(a) levels and both apo(a) fractional clearance rates (FCR) and production rates (PR) in 32 individuals not on lipid-lowering treatment. We determined plasma Lp(a) levels and apo(a) isoform sizes, and used the relative expression of the two isoforms to calculate a "weighted isoform size" (wIS). Stable isotope studies were performed, using D3-leucine, to determine the apo(a) FCR and PR. As expected, plasma Lp(a) concentrations were inversely correlated with wIS (R2 = 0.27; P = 0.002). The wIS had a modest positive correlation with apo(a) FCR (R2 = 0.10, P = 0.08), and a negative correlation with apo(a) PR (R2 = 0.11; P = 0.06). The relationship between wIS and PR became significant when we controlled for self-reported race and ethnicity (SRRE) (R2 = 0.24, P = 0.03); controlling for SRRE did not affect the relationship between wIS and FCR. Apo(a) wIS plays a role in both FCR and PR; however, adjusting for SRRE strengthens the correlation between wIS and PR, suggesting an effect of ancestry.
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Affiliation(s)
- Anastasiya Matveyenko
- Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Nelsa Matienzo
- Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Henry Ginsberg
- Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Renu Nandakumar
- Irving Institute for Clinical and Translational Research, Columbia University, New York, NY, USA
| | - Heather Seid
- Irving Institute for Clinical and Translational Research, Columbia University, New York, NY, USA
| | - Rajasekhar Ramakrishnan
- Center for Biomathematics, Department of Pediatrics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Steve Holleran
- Center for Biomathematics, Department of Pediatrics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Tiffany Thomas
- Department of Pathology and Cell Biology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Gissette Reyes-Soffer
- Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.
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Reyes-soffer G, Matveyenko A, Lignos J, Matienzo N, Santos Baez L, Yung LY, Ramakrishnan R, George RT, Ginsberg HN. Abstract P182: Recombinant Human Lecithin-cholesterol Acyltransferase Treatment In Patients With ASCVD Increases HDL Through Increases In Cholesterol Ester Content. Arterioscler Thromb Vasc Biol 2021. [DOI: 10.1161/atvb.41.suppl_1.p182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Lecithin-cholesterol acyltransferase (LCAT) mediates the esterification of free cholesterol (FC) to cholesteryl ester (CE) in HDL and, therefore, plays a critical role in reverse cholesterol transport. MEDI6012, a recombinant human LCAT (rhLCAT) increases HDL-C. Our goal was to interrogate the pathways regulating the increase in HDL-C and effects of rhLCAT on apoB metabolism.
Methods:
We enrolled five subjects (4 Man, mean age 67) with stable ASCVD into a Phase II, placebo controlled, double-blind, randomized cross-over study to determine the effects of two IV doses of MEDI6012, administered 48-hrs apart, versus placebo, on plasma lipids and lipoproteins. Stable isotope kinetic studies with D2-Leu, 13C-Phe, D2-Glycerol were performed to examine the metabolism of apoB100, ApoA1, ApoA2 and triglyceride.
Results:
As expected two doses of IV MEDI6012 increased total cholesterol and HDL-C levels significantly (Table1). We did not observe significant changes in other measured lipids or lipoproteins. The significant increase in HDL-C was 34.9±10.3 (p=0.002) and due to an increase in the amount of CE (33±8.9 p=0.001); there was no change in free cholesterol (1.9±1.9). We found no changes in levels of sterols (i.e. Lathosterol) between the two periods. Preliminary in vivo kinetic studies of HDL metabolism in 3 subjects, showed no changes in the mean fractional clearance rate (FCR) or production rate (PR) of apoA1 between placebo (0.3±0.2pool/day, 1.3±0.5 mg/kg/day) and rhLCAT treatment (0.28±0.1pools/day, 1.3±0.3). There were no changes in ApoA2 FCR and PR after rhLCAT administration. Complete data for ApoA1, ApoA2 and ApoB100 and TG kinetics will be presented.
Conclusions:
In subjects with ASCVD, treatment with rhLCAT increased HDL-C mainly by increasing HDL CE; there were no changes in the FCR or PR of HDL ApoA1 or ApoA2. Together, these results suggest that rhLCAT treatment is associated with increased steady-state transport of CE by HDL.
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Affiliation(s)
| | | | - James Lignos
- Columbia Univ Med Cntr, College of Physicians and Surgeons, New York, NY
| | - Nelsa Matienzo
- Columbia Univ Med Cntr, College of Physicians and Surgeons, New York, NY
| | - Leinys Santos Baez
- Columbia Univ Med Cntr, College of Physicians and Surgeons, New York, NY
| | - Lau Y Yung
- Columbia Univ Med Cntr, College of Physicians and Surgeons, New York, NY
| | | | | | - Henry N Ginsberg
- Columbia Univ Med Cntr, College of Physicians and Surgeons, New York, NY
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Matveyenko A, Thomas T, Matienzo N, Ramakrishnan R, Seid H, Ginsberg H, Soni R, Soffer G. Relationship between plasma apolipoproteinc3 and plasma lipoprotein(a) levels in a diverse, healthy population. Atherosclerosis 2021. [DOI: 10.1016/j.atherosclerosis.2021.06.339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Matveyenko A, Matienzo N, Thomas T, Ramakrishnan S, Seid H, Ginsberg H, Soffer G. Relationship of Plasma ApolipoproteinC3 with Plasma Lipoprotein(a). FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.02066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Nelsa Matienzo
- MedicineColumbia University Irving Medical CenterNew YorkNY
| | | | - Sekhar Ramakrishnan
- Dept of Pediatrics BioMathColumbia University Irving Medical CenterNew YorkNY
| | - Heather Seid
- Irving Inst Clin/Transltnl ResColumbia University Irving Medical CenterNew YorkNY
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Reyes-Soffer G, Sztalryd C, Horenstein RB, Holleran S, Matveyenko A, Thomas T, Nandakumar R, Ngai C, Karmally W, Ginsberg HN, Ramakrishnan R, Pollin TI. Effects of APOC3 Heterozygous Deficiency on Plasma Lipid and Lipoprotein Metabolism. Arterioscler Thromb Vasc Biol 2019; 39:63-72. [PMID: 30580564 DOI: 10.1161/atvbaha.118.311476] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Objective- Apo (apolipoprotein) CIII inhibits lipoprotein lipase (LpL)-mediated lipolysis of VLDL (very-low-density lipoprotein) triglyceride (TG) and decreases hepatic uptake of VLDL remnants. The discovery that 5% of Lancaster Old Order Amish are heterozygous for the APOC3 R19X null mutation provided the opportunity to determine the effects of a naturally occurring reduction in apo CIII levels on the metabolism of atherogenic containing lipoproteins. Approach and Results- We conducted stable isotope studies of VLDL-TG and apoB100 in 5 individuals heterozygous for the null mutation APOC3 R19X (CT) and their unaffected (CC) siblings. Fractional clearance rates and production rates of VLDL-TG and apoB100 in VLDL, IDL (intermediate-density lipoprotein), LDL, apo CIII, and apo CII were determined. Affected (CT) individuals had 49% reduction in plasma apo CIII levels compared with CCs ( P<0.01) and reduced plasma levels of TG (35%, P<0.02), VLDL-TG (45%, P<0.02), and VLDL-apoB100 (36%, P<0.05). These changes were because of higher fractional clearance rates of VLDL-TG and VLDL-apoB100 with no differences in production rates. CTs had higher rates of the conversion of VLDL remnants to LDL compared with CCs. In contrast, rates of direct removal of VLDL remnants did not differ between the groups. As a result, the flux of apoB100 from VLDL to LDL was not reduced, and the plasma levels of LDL-cholesterol and LDL-apoB100 were not lower in the CT group. Apo CIII production rate was lower in CTs compared with CCs, whereas apo CII production rate was not different between the 2 groups. The fractional clearance rates of both apo CIII and apo CII were higher in CTs than CCs. Conclusions- These studies demonstrate that 50% reductions in plasma apo CIII, in otherwise healthy subjects, results in a significantly higher rate of conversion of VLDL to LDL, with little effect on direct hepatic uptake of VLDL. When put in the context of studies demonstrating significant protection from cardiovascular events in individuals with loss of function variants in the APOC3 gene, our results provide strong evidence that therapies which increase the efficiency of conversion of VLDL to LDL, thereby reducing remnant concentrations, should reduce the risk of cardiovascular disease.
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Affiliation(s)
- Gissette Reyes-Soffer
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Carol Sztalryd
- Maryland School of Medicine, University of Maryland, Baltimore (C.S., R.B.H., T.I.P.)
- Baltimore VA Medical Center, VA Research Service, Geriatric Research, Education and Clinical Center and VA Maryland Health Care System (C.S., T.I.P.)
| | - Richard B Horenstein
- Maryland School of Medicine, University of Maryland, Baltimore (C.S., R.B.H., T.I.P.)
| | - Stephen Holleran
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Anastasiya Matveyenko
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Tiffany Thomas
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Renu Nandakumar
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Colleen Ngai
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Wahida Karmally
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Henry N Ginsberg
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Rajasekhar Ramakrishnan
- From the Columbia University Vagelos College of Physicians and Surgeons, New York (G.R.-S., S.H., A.M., T.T., R.N., C.N., W.K., H.N.G., R.R.)
| | - Toni I Pollin
- Maryland School of Medicine, University of Maryland, Baltimore (C.S., R.B.H., T.I.P.)
- Baltimore VA Medical Center, VA Research Service, Geriatric Research, Education and Clinical Center and VA Maryland Health Care System (C.S., T.I.P.)
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Nandakumar R, Matveyenko A, Thomas T, Pavlyha M, Ngai C, Holleran S, Ramakrishnan R, Ginsberg HN, Karmally W, Marcovina SM, Reyes-Soffer G. Effects of mipomersen, an apolipoprotein B100 antisense, on lipoprotein (a) metabolism in healthy subjects. J Lipid Res 2018; 59:2397-2402. [PMID: 30293969 DOI: 10.1194/jlr.p082834] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 09/25/2018] [Indexed: 01/17/2023] Open
Abstract
Elevated lipoprotein (a) [Lp(a)] levels increase the risk for CVD. Novel treatments that decrease LDL cholesterol (LDL-C) have also shown promise for reducing Lp(a) levels. Mipomersen, an antisense oligonucleotide that inhibits apoB synthesis, is approved for the treatment of homozygous familial hypercholesterolemia. It decreases plasma levels of LDL-C by 25% to 39% and lowers levels of Lp(a) by 21% to 39%. We examined the mechanisms for Lp(a) lowering during mipomersen treatment. We enrolled 14 healthy volunteers who received weekly placebo injections for 3 weeks followed by weekly injections of mipomersen for 7 weeks. Stable isotope kinetic studies were performed using deuterated leucine at the end of the placebo and mipomersen treatment periods. The fractional catabolic rate (FCR) of Lp(a) was determined from the enrichment of a leucine-containing peptide specific to apo(a) by LC/MS. The production rate (PR) of Lp(a) was calculated from the product of Lp(a) FCR and Lp(a) concentration (converted to pool size). In a diverse population, mipomersen reduced plasma Lp(a) levels by 21%. In the overall study group, mipomersen treatment resulted in a 27% increase in the FCR of Lp(a) with no significant change in PR. However, there was heterogeneity in the response to mipomersen therapy, and changes in both FCRs and PRs affected the degree of change in Lp(a) concentrations. Mipomersen treatment decreases Lp(a) plasma levels mainly by increasing the FCR of Lp(a), although changes in Lp(a) PR were significant predictors of reductions in Lp(a) levels in some subjects.
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Affiliation(s)
- Renu Nandakumar
- Columbia University College of Physicians and Surgeons, New York, NY
| | | | - Tiffany Thomas
- Columbia University College of Physicians and Surgeons, New York, NY
| | - Marianna Pavlyha
- Columbia University College of Physicians and Surgeons, New York, NY
| | - Colleen Ngai
- Columbia University College of Physicians and Surgeons, New York, NY
| | - Stephen Holleran
- Columbia University College of Physicians and Surgeons, New York, NY
| | | | - Henry N Ginsberg
- Columbia University College of Physicians and Surgeons, New York, NY
| | - Wahida Karmally
- Columbia University College of Physicians and Surgeons, New York, NY
| | - Santica M Marcovina
- Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle, WA
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Abstract
UNLABELLED Telomeres consist of TTAGGG repeats bound by the shelterin complex and end with a 3' overhang. In humans, telomeres shorten at each cell division, unless telomerase (TERT) is expressed and able to add telomeric repeats. For effective telomere maintenance, the DNA strand complementary to that made by telomerase must be synthesized. Recent studies have discovered a link between different activities necessary to process telomeres in the S phase of the cell cycle to reform a proper overhang. Notably, the human CST complex (CTC1/STN1/TEN1), known to interact functionally with the polymerase complex (POLA/primase), was shown to be important for telomere processing. Here, focus was paid to the catalytic (POLA1/p180) and accessory (POLA2/p68) subunits of the polymerase, and their mechanistic roles at telomeres. We were able to detect p68 and p180 at telomeres in S-phase using chromatin immunoprecipitation. We could also show that the CST, shelterin, and polymerase complexes interact, revealing contacts occurring at telomeres. We found that the polymerase complex could associate with telomerase activity. Finally, depletion of p180 by siRNA led to increased overhang amounts at telomeres. These data support a model in which the polymerase complex is important for proper telomeric overhang processing through fill-in synthesis, during S phase. These results shed light on important events necessary for efficient telomere maintenance and protection. IMPLICATIONS This study describes the interplay between DNA replication components with proteins that associate with chromosome ends, and telomerase. These interactions are proposed to be important for the processing and protection of chromosome ends.
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Affiliation(s)
- Raffaella Diotti
- Department of Biological Sciences, Hunter College and CUNY Graduate Center, New York, New York
| | - Sampada Kalan
- Department of Biological Sciences, Hunter College and CUNY Graduate Center, New York, New York
| | - Anastasiya Matveyenko
- Department of Biological Sciences, Hunter College and CUNY Graduate Center, New York, New York
| | - Diego Loayza
- Department of Biological Sciences, Hunter College and CUNY Graduate Center, New York, New York.
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Kalan S, Matveyenko A, Loayza D. LIM Protein Ajuba Participates in the Repression of the ATR-Mediated DNA Damage Response. Front Genet 2013; 4:95. [PMID: 23755068 PMCID: PMC3664778 DOI: 10.3389/fgene.2013.00095] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 05/07/2013] [Indexed: 01/06/2023] Open
Abstract
LIM proteins constitute a superfamily characterized by the presence of a LIM domain, known to be involved in protein-protein interactions. Our previous work has implicated members of the Zyxin family of LIM proteins, namely TRIP6 and LPP, in the repression of the DNA damage response (DDR) at telomeres. Here, we describe a role for Ajuba, a closely related LIM molecule, in repressing the ATR-mediated DDR. We found that depletion of Ajuba led to apparent delays in the cell cycle, accompanied with increased Rb phosphorylation, Chk1 phosphorylation, induction of p53, and cell death. Ajuba could be found in a complex with replication protein A (RPA), and its depletion led to RPA phosphorylation, known to be an early event in ATR activation. We propose that Ajuba protects against unscheduled ATR signaling by preventing inappropriate RPA phosphorylation.
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Affiliation(s)
- Sampada Kalan
- Department of Biological Sciences, Hunter College , New York, NY , USA
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13
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Kalan S, Matveyenko A, Loayza D. A potential role for LIM protein Ajuba in repression of DNA damage response in human cells. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.546.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sampada Kalan
- Hunter CollegeCity University of New YorkNew YorkNY
- Graduate CenterCity University of New YorkNew YorkNY
| | | | - Diego Loayza
- Hunter CollegeCity University of New YorkNew YorkNY
- Graduate CenterCity University of New YorkNew YorkNY
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Butler AE, Galasso R, Matveyenko A, Rizza RA, Dry S, Butler PC. Pancreatic duct replication is increased with obesity and type 2 diabetes in humans. Diabetologia 2010; 53:21-6. [PMID: 19844672 PMCID: PMC2789928 DOI: 10.1007/s00125-009-1556-8] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Accepted: 09/15/2009] [Indexed: 12/15/2022]
Abstract
AIMS/HYPOTHESIS In a high-fat-fed rat model of type 2 diabetes we noted increased exocrine duct replication. This is a predisposing factor for pancreatitis and pancreatic cancer, both of which are more common in type 2 diabetes. The aim of the study reported here was to establish if obesity and/or type 2 diabetes are associated with increased pancreatic ductal replication in humans. METHODS We obtained pancreas at autopsy from 45 humans, divided into four groups: lean (BMI <25 kg/m(2)); obese (BMI >27 kg/m(2)); non-diabetic; and with type 2 diabetes. Pancreases were evaluated after immunostaining for the duct cell marker cytokeratin and Ki67 for replication. RESULTS We show for the first time that both obesity and type 2 diabetes in humans are associated with increased pancreatic ductal replication. Specifically, we report that (1) replication of pancreatic duct cells is increased tenfold by obesity, and (2) lean subjects with type 2 diabetes demonstrate a fourfold increase in replication of pancreatic duct cells compared with their lean non-diabetic controls. CONCLUSIONS/INTERPRETATION Pancreatic duct cell replication is increased in humans in response to both obesity and type 2 diabetes, potentially providing a mechanism for the increased risk of pancreatitis and pancreatic cancer in those with obesity and/or type 2 diabetes.
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Affiliation(s)
- A. E. Butler
- Larry Hillblom Islet Research Center, UCLA David Geffen School of Medicine, 900 Weyburn Place #A, Los Angeles, CA 90024-2852 USA
| | - R. Galasso
- Larry Hillblom Islet Research Center, UCLA David Geffen School of Medicine, 900 Weyburn Place #A, Los Angeles, CA 90024-2852 USA
| | - A. Matveyenko
- Larry Hillblom Islet Research Center, UCLA David Geffen School of Medicine, 900 Weyburn Place #A, Los Angeles, CA 90024-2852 USA
| | - R. A. Rizza
- Endocrine Research Unit, Mayo Medical College, Rochester, MN USA
| | - S. Dry
- Department of Pathology, UCLA David Geffen School of Medicine, Los Angeles, CA USA
| | - P. C. Butler
- Larry Hillblom Islet Research Center, UCLA David Geffen School of Medicine, 900 Weyburn Place #A, Los Angeles, CA 90024-2852 USA
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