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PubMed1997

Characterization of two vaccinia CD36 recombinant-virus-generated monoclonal antibodies (10/5, 13/10): effects on malarial cytoadherence and platelet functions.

Extensive evidence is now available to show that the human CD36 antigen is a cellular receptor for thrombospondin, collagen, modified low-density lipoproteins, and long-chain fatty acids. Moreover, CD36 functions as one of the receptors that mediates the adhesion of Plasmodium-falciparum-infected erythrocytes to microvascular endothelium. In an attempt to identify new functional sites of this surface glycoprotein, anti-CD36 monoclonal antibodies were prepared using a vaccinia CD36 recombinant virus as a highly efficient immunization vector. In functional studies, one of these antibodies (clone 10/5) strongly inhibited the adhesion of P. falciparum-infected erythrocytes to purified CD36. This antibody also potentiated ADP-induced platelet activation. In contrast, a second antibody (clone 13/10) did not affect the cytoadherence of infected erythrocytes or platelet functions. Previous structural work performed on these antibodies has shown that clone 10/5 is directed against an epitope within the CD36 domain 155-183, whereas clone 13/10 interacts with another antigenic determinant defined by amino acids 30-76 [Daviet, L., Buckland, R., Puente Navazo, M. D. & McGregor, J. L. (1995) Biochem. J. 305, 221-224]. Taken together, these current studies show that: (a) the methodology of immunization using recombinant vaccinia virus is a powerful tool in the generation of monoclonal antibodies directed against polyimmunogenic membrane glycoproteins such as CD36; (b) the CD36 domain, recognized by clone 10/5 but not by 13/10, is functionnally important regarding the adhesion of P. falciparum-infected erythrocyte and CD36-dependent platelet activation.

Animals↗
PubMed2026

Molecular characterization of CD36 deficiency in blood donors of Middle Eastern and African origin reveals transcript-level defects beyond genomic variants.

BACKGROUND: The increasing diversity of blood donor populations has created new challenges for transfusion services worldwide. The identification of donors lacking relevant high-prevalence antigens is becoming increasingly important to ensure compatible blood products for alloimmunized patients and to support the development of rare donor registries. CD36 (ISBT 045) is a glycoprotein expressed on platelets, monocytes, and erythroid precursor cells. CD36 deficiency has been reported across multiple populations and is of relevance due to its association with anti-CD36 isoantibodies, which may cause platelet transfusion refractoriness and fetal/neonatal alloimmune thrombocytopenia. STUDY DESIGN AND METHODS: We analyzed CD36 expression in 1250 blood donors of diverse ancestry using flow cytometry. CD36-negative samples underwent molecular characterization using Sanger sequencing and next-generation sequencing of genomic DNA, complemented by cDNA analysis and cloning to investigate transcript-level alterations. RESULTS: We identified CD36 deficiency in 27 donors (2.16%). Genomic sequencing revealed 18 distinct coding variants, including three novel variants, most in the heterozygous state. In one CD36-negative donor, cDNA analysis demonstrated a 52-bp deletion in exon four and complete skipping of exon 9, despite the absence of splice-site variants in genomic DNA. Cloning confirmed coexistence of aberrant and wild-type transcripts in this individual. CONCLUSION: Our findings demonstrate that CD36 deficiency can arise from transcript-level defects in the absence of detectable coding or splice-site variants. These results indicate that genomic sequencing alone may be insufficient to fully resolve CD36-negative phenotypes and highlight the importance of integrating transcriptomic approaches to improve molecular diagnostics and transfusion support in increasingly diverse donor populations.

CD36 deficiency↗
PubMed2003

CD36-mediated nonopsonic phagocytosis of erythrocytes infected with stage I and IIA gametocytes of Plasmodium falciparum.

Gametocytes, the sexual stages of malaria parasites (Plasmodium spp.) that are transmissible to mosquitoes, have been the focus of much recent research as potential targets for novel drug and vaccine therapies. However, little is known about the host clearance of gametocyte-infected erythrocytes (GEs). Using a number of experimental strategies, we found that the scavenger receptor CD36 mediates the uptake of nonopsonized erythrocytes infected with stage I and IIA gametocytes of Plasmodium falciparum by monocytes and culture-derived macrophages (Mphis). Light microscopy and immunofluorescence assays revealed that stage I and IIA gametocytes were readily internalized by monocytes and Mphis. Pretreating monocytes and Mphis with a monoclonal antibody that blocked CD36 resulted in a significant reduction in phagocytosis, as did treating GEs with low concentrations of trypsin to remove P. falciparum erythrocyte membrane protein 1 (PfEMP-1), a parasite ligand for CD36. Pretreating monocytes and Mphis with peroxisome proliferator-activated receptor gamma-retinoid X receptor agonists, which specifically upregulate CD36, resulted in a significant increase in the phagocytosis of GEs. Murine CD36 on mouse Mphis also mediated the phagocytosis of P. falciparum stage I and IIA gametocytes, as determined by receptor blockade with anti-murine CD36 monoclonal antibodies and the lack of uptake by CD36-null Mphis. These results indicate that phagocytosis of stage I and IIA gametocytes by monocytes and Mphis appears to be mediated to a large extent by the interaction of PfEMP-1 and CD36, suggesting that CD36 may play a role in innate clearance of these early sexual stages.

Animals↗
PubMed1996

Antibodies to CD36 (GPIV) inhibit platelet adhesion to subendothelial surfaces under flow conditions.

The membrane glycoprotein CD36 (glycoprotein [GP] IV) has previously been shown to accelerate the initial interaction of platelets with purified type I collagen in both static and flow systems. In the present study, the role of CD36 on platelet interaction with physiologically relevant collagenous surfaces was addressed. Using arterial subendothelium (SE) and endothelial cell extracellular matrix (ECM), studies were performed under flow conditions with annular and parallel-plate perfusion chambers, respectively, at a shear rate of 800 s-1 for 2, 5, and 10 minutes. Perfusates consisted of citrated normal blood samples incubated with Fab fragments of a monospecific polyclonal anti-CD36 antibody or with each of three new anti-CD36 monoclonal antibodies (MoAbs) that inhibit platelet adhesion to purified type I collagen in a static system (131.4, 131.5, and 131.7). Perfusions over SE were also carried out using citrated blood samples from a Naka-negative donor, whose platelets lack CD36. Morphometric evaluation of the perfused samples showed that polyclonal anti-CD36 Fab and the three monoclonal anti-CD36 antibodies inhibited platelet adhesion to the two substrates by 40% after 2 minutes of perfusion and by 30% after 5 minutes (P < .005 on SE and P < .01 on ECM), but at 10 minutes, significant inhibition was seen only on SE with polyclonal anti-CD36 Fab. Similar inhibitions were seen with Naka-negative platelets on SE. These studies demonstrate that CD36 plays a role in the early stages of platelet adhesion to physiologically relevant subendothelial surfaces.

Antibodies, Monoclonal↗
PubMed1996

Identification on human CD36 of a domain (155-183) implicated in binding oxidized low-density lipoproteins (Ox-LDL).

Uptake of oxidized LDL (oxLDL) by macrophages is one of the key events implicated in the initiation and perpetuation of atherosclerotic lesions. One of the major scavenging receptors, which binds modified LDL, on macrophages is CD36. The domain on CD36 implicated in the binding of oxLDL remains to be elucidated. In this study, COS cells transfected with human CD36 cDNA bound FITC-oxidized human LDL in a dose-dependent, saturable manner. This binding was inhibited by an excess of oxLDL but not by native LDL. Anti-CD36 monoclonal antibodies (mAbs) 10/5, FA6-152, and 8A6 (directed against domain 155-183), but not mAb 13/10 (directed against domain 30-76), completely inhibited oxLDL binding to human CD36-transfected COS cells. Cells transfected with a chimeric human CD36 construct (hmh 155-183), resulting from the swapping of human domain 155-183 with its murine counterpart, resulted in low binding of oxLDL. In contrast, cells transfected with a chimeric murine CD36 construct (mhm 155-183), resulting from the swapping of murine domain 155-183 with its human counterpart, resulted in high binding of oxidized human LDL. Binding of oxLDL to cells transfected by chimeric construct mhm 155-183 were only partially blocked by mAbs 10/5, FA6-152, and 8A6. In the present study we have identified, for the first time, an important functional domain (encompassing amino acids 155-183) on CD36 involved in the binding of oxLDL. In addition, the binding site for oxidized human LDL on murine CD36 seems to differ from its human counterpart.

Animals↗
PubMed2000

Expression of macrophage (Mphi) scavenger receptor, CD36, in cultured human aortic smooth muscle cells in association with expression of peroxisome proliferator activated receptor-gamma, which regulates gain of Mphi-like phenotype in vitro, and its implication in atherogenesis.

CD36 is one of the major receptors for oxidized low density lipoproteins belonging to macrophage (Mphi) scavenger receptor (SR) class B and is thought to play an important role in the foam cell formation from monocyte-Mphi in the atherosclerotic lesions. Although it has been hypothesized that smooth muscle cells (SMCs) may be the other origin of foam cells in vivo, supporting data are still very limited. In the present study, we have tested the expression of a variety of SRs, including CD36, in 8 lots of primary human aortic SMCs (HASMCs) explanted from 8 different donors. Functional CD36 was expressed in cultured HASMCs, and the levels of expression were widely ranged between the lots. SR class A (SR-A) was expressed abundantly in CD36-negative lots. Other Mphi markers, such as CD32 and CD68, were expressed in all lots tested. These data suggest that the cultured HASMCs gained an Mphi-like phenotype. To determine the mechanism for the above-described phenotypic change, we have tested the expression of a nuclear receptor, peroxisome proliferator activated receptor-gamma, in those cells. This nuclear receptor was abundantly expressed in CD36-positive lots, whereas c-fms was expressed abundantly in CD36-negative/SR-A-positive lots. The synthetic ligand of peroxisome proliferator activated receptor-gamma, troglitazone, upregulated the expression of CD36 only in CD36-positive lots. These observations demonstrate that cultured HASMCs can gain an Mphi-like phenotype, possibly classified by the expression of CD36 or SR-A. The present study may support the possibilities of transformation of HASMCs into foam cells in vivo.

Adult↗
PubMed1995

Heart CD36 expression is increased in murine models of diabetes and in mice fed a high fat diet.

High levels of CD36 expression are found in triglyceride storing and secreting cells such as differentiated adipocytes and mammary secretory epithelial cells and in some capillary endothelial cells. We have found high levels of CD36 in the capillary endothelium of murine adipose tissue and in cardiac and skeletal muscles. Muscle cells themselves were CD36 negative. No CD36 was found in brain endothelium. Cardiac and skeletal muscle tissues are highly oxidative and catabolize long-chain fatty acids as a source of energy while brain tissue does not use long-chain fatty acids for energy production. Since capillary endothelial cell CD36 expression appeared to correlate with parenchymal cell fatty acid utilization and since CD26 has been identified recently as a long-chain fatty acid-binding protein, we examined heart tissue CD36 expression in murine models of insulin-dependent (nonobese diabetic, NOD) and non-insulin-dependent diabetes mellitus (KKAY). Diabetic NOD and KKAY mice had serum triglyceride levels 2.6- and 4.2-fold higher, respectively, than normal mice and exhibited 7- and 3.5-fold higher levels of heart microsomal CD36, respectively, than control mice. Mice fed a 40% fat diet expressed heart tissue CD36 at a level 3.5-fold higher than those fed a 9% fat diet. These data suggest that endothelial cell CD36 expression is related to parenchymal cell lipid metabolism.

Animals↗
PubMed1995

Reduced uptake of oxidized low density lipoproteins in monocyte-derived macrophages from CD36-deficient subjects.

To clarify the physiological roles of CD36 as an oxidized low density lipoprotein (OxLDL) receptor, we analyzed the monocyte-derived macrophages from normal and two CD36-deficient subjects, since we identified the molecular abnormalities (Kashiwagi, H., Y. Tomiyama, Y. Kosugi, M. Shiraga, R. H. Lipsky, Y. Kanayama, Y. Kurata, and Y. Matsuzawa 1994. Blood. 83:3545-3552; and Kashiwagi, H., Y. Tomiyama, S. Honda, S. Kosugi, M. Shiraga, N. Nagao, S. Sekiguchi, Y. Kanayama, Y. Kurata, and Y. Matsuzawa. 1995. J. Clin. Invest. 95:1040-1046). Scatchard analysis of 125I-OxLDL binding showed a linear plot and the maximum binding was lower by approximately 40% in the macrophages from subjects with CD36 deficiency than those from normal controls. Competition studies showed that the uptake of 125I-OxLDL was suppressed by OKM5, an antibody against CD36, by 53% in normal control macrophages, but not in the CD36-deficient macrophages. After incubation with OxLDL for 24 h, cholesteryl ester mass accumulation was reduced by approximately 40% in the macrophages from CD36-deficient subjects than those from normal controls. These results suggest that CD36 is one of the physiological receptors for OxLDL. Since specific binding of OxLDL was only reduced by approximately 40% in spite of the complete deficiency of CD36, several other receptors also may have some role in OxLDL uptake. Further studies will be needed to assess the quantitative role of CD36 in foam cell formation in vivo.

Adult↗
PubMed2000

Macrophage scavenger receptor CD36 is the major receptor for LDL modified by monocyte-generated reactive nitrogen species.

The oxidative conversion of LDL into an atherogenic form is considered a pivotal event in the development of cardiovascular disease. Recent studies have identified reactive nitrogen species generated by monocytes by way of the myeloperoxidase-hydrogen peroxide-nitrite (MPO-H(2)O(2)-NO(2)(-)) system as a novel mechanism for converting LDL into a high-uptake form (NO(2)-LDL) for macrophages. We now identify the scavenger receptor CD36 as the major receptor responsible for high-affinity and saturable cellular recognition of NO(2)-LDL by murine and human macrophages. Using cells stably transfected with CD36, CD36-specific blocking mAbs, and CD36-null macrophages, we demonstrated CD36-dependent binding, cholesterol loading, and macrophage foam cell formation after exposure to NO(2)-LDL. Modification of LDL by the MPO-H(2)O(2)-NO(2)(-) system in the presence of up to 80% lipoprotein-deficient serum (LPDS) still resulted in the conversion of the lipoprotein into a high-uptake form for macrophages, whereas addition of less than 5% LPDS totally blocked Cu(2+)-catalyzed LDL oxidation and conversion into a ligand for CD36. Competition studies demonstrated that lipid oxidation products derived from 1-palmitoyl-2-arachidonyl-sn-glycero-3-phosphocholine can serve as essential moieties on NO(2)-LDL recognized by CD36. Collectively, these results suggest that MPO-dependent conversion of LDL into a ligand for CD36 is a likely pathway for generating foam cells in vivo. MPO secreted from activated phagocytes may also tag phospholipid-containing targets for removal by CD36-positive cells.

Animals↗
PubMed2005

Multiple metabolic hits converge on CD36 as novel mediator of tubular epithelial apoptosis in diabetic nephropathy.

BACKGROUND: Diabetic nephropathy (DNP) is a common complication of type 1 and type 2 diabetes mellitus and the most common cause of kidney failure. While DNP manifests with albuminuria and diabetic glomerulopathy, its progression correlates best with tubular epithelial degeneration (TED) and interstitial fibrosis. However, mechanisms leading to TED in DNP remain poorly understood. METHODS AND FINDINGS: We found that expression of scavenger receptor CD36 coincided with proximal tubular epithelial cell (PTEC) apoptosis and TED specifically in human DNP. High glucose stimulated cell surface expression of CD36 in PTECs. CD36 expression was necessary and sufficient to mediate PTEC apoptosis induced by glycated albumins (AGE-BSA and CML-BSA) and free fatty acid palmitate through sequential activation of src kinase, and proapoptotic p38 MAPK and caspase 3. In contrast, paucity of expression of CD36 in PTECs in diabetic mice with diabetic glomerulopathy was associated with normal tubular epithelium and the absence of tubular apoptosis. Mouse PTECs lacked CD36 and were resistant to AGE-BSA-induced apoptosis. Recombinant expression of CD36 in mouse PTECs conferred susceptibility to AGE-BSA-induced apoptosis. CONCLUSION: Our findings suggest a novel role for CD36 as an essential mediator of proximal tubular apoptosis in human DNP. Because CD36 expression was induced by glucose in PTECs, and because increased CD36 mediated AGE-BSA-, CML-BSA-, and palmitate-induced PTEC apoptosis, we propose a two-step metabolic hit model for TED, a hallmark of progression in DNP.

Animals↗
PubMed2005

The class B scavenger receptor CD36 mediates free radical production and tissue injury in cerebral ischemia.

The class B scavenger receptor CD36 is involved in the cytotoxicity associated with inflammation, but its role in the inflammatory reaction that accompanies cerebral ischemia has not been examined. In this study, we investigated whether CD36 contributes to the brain damage produced by cerebral ischemia. The middle cerebral artery was transiently occluded in wild-type mice and in mice deficient in CD36. In wild-type mice, CD36 protein expression was increased in the ischemic brain, such that it was located predominantly in cells expressing the microglia/macrophage marker CD11b. The infarct produced by middle cerebral artery occlusion was 49% smaller in CD36-null mice than in wild-type controls, an effect associated with improved neurological function. The attenuation in brain injury in CD36 nulls could not be attributed to differences in cerebral blood flow during ischemia-reperfusion. However, the increase in reactive oxygen species (ROS) produced by cerebral ischemia was markedly attenuated in CD36-null mice in the early stage after reperfusion. The data unveil a previously unrecognized role of CD36 in ischemia-induced ROS production and brain injury. Modulation of CD36 signaling may provide a new strategy for the treatment of ischemic stroke.

Animals↗
PubMedDate not supplied

Link between anti-CD36 antibodies and thrombosis in the antiphospholipid syndrome.

OBJECTIVE: Some studies have previously suggested the involvement of antibodies directed against CD36 (anti-CD36) in the pathogenesis of thrombosis. The aim of this study was to evaluate the prevalence of anti-CD36 in patients with antiphospholipid antibodies (aPL) and its relationship with thrombosis. METHODS: Anti-CD36 were tested using an indirect MAIPA assay in 62 patients with autoimmune aPL but without SLE; there were 38 with and 24 without thrombosis. Nineteen patients with thrombosis served as an aPL(-) control group and 58 healthy subjects as the normal control group. RESULTS: 15 of 62 aPL patients (24.2%) but only 1 of 58 (1.7%) normal controls had anti-CD36 (p < 0.0005). As compared to normal controls, the prevalence of anti-CD36 was significantly higher in aPL patients with (26.3%, p < 0.0005) or without thrombosis (20.8%, p < 0.01). Anti-CD36 were significantly more frequent in aPL patients with thrombosis than in thrombosis aPL(-) subjects (26.3% vs 0%, p = 0.02). The presence of anti-CD36 seems to be more frequent in aPL patients with recurrent thrombosis than in those with a single episode (36.8% vs 15.8%). CONCLUSION: The presence of anti-CD36 is highly prevalent in patients with autoimmune aPL with a trend to being more frequent in patients with recurrent episodes of thrombosis.

Adult↗
PubMed2003

Transgenic expression of CD36 in the spontaneously hypertensive rat is associated with amelioration of metabolic disturbances but has no effect on hypertension.

Spontaneously hypertensive rats (SHR/NIH strain) harbor a deletion variant in the Cd36 fatty acid transporter and display defective fatty acid metabolism, insulin resistance and hypertension. Transgenic rescue of Cd36 in SHR ameliorates insulin resistance and improves dyslipidemia. However, the role of Cd36 in blood pressure regulation remains controversial due to inconsistent blood pressure effects that were observed with transgenic expression of Cd36 on the SHR background. In the current studies, we developed two new SHR transgenic lines, which express wild type Cd36 under the control of the universal Ef-1 alpha promoter, and examined the effects of transgenic expression of wild type Cd36 on selected metabolic and cardiovascular phenotypes. Transgenic expression of Cd36 in the new lines was associated with significantly decreased serum fatty acids, amelioration of insulin resistance and glucose intolerance but failed to induce any consistent changes in blood pressure as measured by radiotelemetry. The current findings confirm the genetic association of defective Cd36 with disordered insulin action and fatty acid metabolism in the SHR/NIH strain and suggest that Cd36 is linked to other gene(s) on rat chromosome 4 that regulate blood pressure.

Adipose Tissue↗
PubMed2005

Increased CD36 expression on circulating monocytes during HIV infection.

BACKGROUND: Metabolic alterations and abnormalities of fat distribution are common findings in antiretroviral-treated HIV-1-infected patients. CD36 is a multifunctional receptor with a wide tissue distribution that plays a crucial role in the cellular uptake and metabolism of lipids. OBJECTIVES: To define the level of CD36 expression on circulating monocytes from HIV-1-infected patients and healthy controls (HCs) and to correlate CD36 expression levels with metabolic and immunovirologic parameters. METHODS: CD36 expression on peripheral blood monocytes was measured by means of flow cytometry in 165 HIV-1-infected patients and in 35 HCs. Statistical analysis was performed by means of univariate and multivariate analysis of variance models. RESULTS: CD36 expression was significantly higher in HIV-1-infected patients compared with HCs (P < 0.0001). HIV-1 infection was the only variable associated with CD36 expression on multivariate analysis, whereas no correlation was found between CD36 level and age, sex, body mass index, lipid serum levels, HIV RNA levels, time on antiretroviral therapy, or kind of antiretroviral regimen. CONCLUSIONS: HIV-1 infection is associated with increased expression of CD36 on circulating monocytes, and antiretroviral drugs play only a minor role in the complex homeostasis of this receptor. Given its role in the cellular uptake and accumulation of lipids, CD36 increased levels on monocytes could represent a proatherogenic condition in HIV-infected patients.

Adult↗
PubMed1994

Structural organization of the gene for human CD36 glycoprotein.

The cell-surface glycoprotein CD36 interacts with a large variety of ligands, including collagen types I and IV, thrombospondin, erythrocytes parasitized with Plasmodium falciparum, platelet-agglutinating protein p37, oxidized low density lipoprotein, and long-chain fatty acids. Its expression is restricted to platelets, monocytes, adipocytes, and some endothelial and epithelial cells and is regulated during cell activation, differentiation, and development. CD36 belongs to a novel gene family of structurally related glycoproteins that includes CLA-1 and the lysosomal membrane glycoprotein LIMPII. To advance our knowledge on the genomic organization and the regulation of the cellular expression of the genes of this family, we have investigated the structural organization of the human CD36 gene and of its 5'-proximal flanking region. The CD36 gene is encoded by 15 exons that extend more than 32 kilobases on the human genome. Interestingly, the CD36 mRNA 5'-untranslated region is encoded by three exons. The 3'-untranslated region is contained in two exons, whose expression pattern can originate two mRNA forms. The cytoplasmic and transmembrane regions predicted at both terminal ends of the polypeptide chain are encoded by single exons, while the extracellular domain is encoded by 11 exons. The transcription initiation site of the CD36 gene is located 289 nucleotides upstream from the translational start codon. Sequence analysis of the proximal 5'-flanking region of the gene reveals the existence of a TATA box appropriately located with respect to the transcription initiation site and several potential cis-regulatory elements that might contribute to the transcriptional regulation of the CD36 gene. Delineation of the structural organization of the CD36 gene may help in defining the boundaries of relevant structural and/or functional domains in CD36 and, by extension, in the other members of the family.

Antigens, CD↗
PubMed2002

Peroxisome-proliferator-activated-receptor gamma (PPARgamma) independent induction of CD36 in THP-1 monocytes by retinoic acid.

Retinoic acid (RA) has been shown to regulate cellular growth and differentiation of a variety of cell types, including cells of the myelomonocytic lineage. We used the monocytic leukaemia cell line THP-1, which differentiates to macrophages in response to phorbol 12-myristate 13-acetate (PMA), to investigate the regulation by RA of genes in the scavenger receptor type B family (CD36) in human monocyte/macrophages. Reverse transcription-polymerase chain reaction and flow cytometry demonstrated that, like PMA and the natural peroxisome-proliferator-activated receptor-gamma (PPARgamma) ligand 15d-PGJ2, RA induced CD36 gene expression in these cells. Moreover, RA plus 15d-PGJ2 further enhanced CD36 protein and mRNA levels over that seen with the RA or PPARgamma compounds alone. The PPARgamma antagonist GW9662 was shown to block completely PPARgamma-ligand induction of CD36 gene expression, but had little effect on the action of RA. Our data indicated that RXR- and RAR-specific ligands (LG153 and TTNPB, respectively) were each alone able to increase CD36 mRNA and surface protein levels. By using calphostin C, a specific protein kinase C (PKC) inhibitor, we demonstrated that induction of CD36 by PMA, as well as by PPARgamma and RXR ligands were dependent upon PKC activation. In contrast, activation of CD36 through the RAR pathway was not affected by inhibition of PKC activity. Taken together, these data demonstrate that RA can up-regulate CD36 expression in human monocytes/macrophages. This regulation appears to be predominantly mediated through the RAR/RXR pathway of action and, unlike previously described methods of CD36 modulation, is independent of PPARgamma and PKC signalling. This study suggests a possible role for RA in physiological processes involving the scavenger receptor function in cells of the monocyte/macrophage lineage.

Cells, Cultured↗
PubMed2026

A Common CD36 Variant and the Genetic Landscape of Dilated Cardiomyopathy in Individuals of African Ancestry.

IMPORTANCE: Dilated cardiomyopathy (DCM) is a major cause of heart failure that disproportionately affects individuals of African genetic ancestry (AFR), among whom familial clustering of disease is also more pronounced relative to those of European ancestry (EUR). However, established monogenic DCM genes, identified primarily in EUR populations, explain a smaller proportion of DCM cases in AFR populations. A recent study identified a common AFR-specific nonsense variant in CD36 that accounts for a substantial burden of DCM in AFR. How the risk and population impact of this variant compare with those of established genetic causes of DCM is unknown. OBJECTIVE: To compare the contribution of a CD36 nonsense variant to DCM risk with that of truncating variants in TTN and pathogenic or likely pathogenic (P/LP) variants in other established DCM genes. DESIGN SETTING AND PARTICIPANTS: Multicohort genetic association study including AFR and EUR participants with exome or genome sequence and DCM case status from four datasets: All of Us, Million Veteran Program, Penn Medicine Biobank, and the DCM Precision Medicine Study. EXPOSURE: Carrier status for TTN truncating variants, P/LP variants in 11 high confidence DCM genes, and the CD36 nonsense variant (Y325*; 0, 1, or 2 copies). MAIN OUTCOMES AND MEASURES: Odds of DCM; prevalence of risk-variant carriers among DCM cases; and population attributable fraction (PAF) for DCM. RESULTS: Among 82,623 AFR individuals across four studies, the mean age was 53.4 years and 1,625 had DCM. CD36 Y325* risk-allele homozygotes had 4.8-fold (95% CI, 3.1-7.3) increased odds of DCM, and CD36 Y325* heterozygotes had 1.4-fold (95% CI, 1.2-1.7) increased odds. TTN truncating variants also conferred elevated risk of DCM in AFR participants (OR, 8.46; 95% CI, 5.3-12.3). Among AFR DCM cases, 2.5% were CD36 homozygotes, second only to TTN truncating variants (4.3%) and exceeding all other high-confidence DCM genes combined (1.5%). In population-level analyses incorporating both heterozygous and homozygous CD36 Y325* carriers, the population-attributable fraction for CD36 (9.0%) surpassed that of TTN truncating variants (3.6%). CONCLUSIONS AND RELEVANCE: An ancestry-specific CD36 variant contributes more to DCM burden in AFR ancestry than established DCM genes, including TTN truncating variants, typically considered the most common genetic cause of DCM. These findings reshape the known genetic architecture of DCM in individuals of African ancestry and highlight the importance of representation in genomic research.

Journal Article↗
PubMed1997

Is CD36 deficiency an etiology of hereditary hypertrophic cardiomyopathy?

Hereditary hypertrophic cardiomyopathy (HCM) is an autosomal dominant disease, but the genetic defects are still unclear in many cases. Reduced myocardial long-chain fatty acid (LCFA) uptake has been demonstrated in patients with some types of HCM. In addition, a possible relationship between a shift ofmyocardial substrate utilization and cardiac hypertrophy has been suggested by experimental studies. Myocardial uptake of LCFAs occurs via a specific transporter, which is homologous with human CD36. CD36 deficiency has also been reported in some individuals, and is transmitted as an autosomal dominant trait like HCM. In this study, we analyzed CD36 in 47 patients with HCM [29 with asymmetric septal hypertrophy (ASH) and 18 without ASH], 11 patients with dilated cardiomyopathy (DCM), and 26 patients with pressure-overload cardiac hypertrophy. Eleven patients (37.9%) who had HCM with ASH, one (9.1%) with DCM, and two (7.7%) with pressure-overload hypertrophy showed CD36 deficiency, while none of the HCM patients without ASH had CD36 deficiency. One patient who had HCM with ASH and CD36 deficiency showed no myocardial LCFA uptake, although myocardial perfusion was normal. Reduced myocardial LCFA uptake despite normal myocardial perfusion was demonstrated in the other HCM patients with ASH and CD36 deficiency. Based on the high prevalence of CD36 deficiency in HCM patients with ASH, we hypothesize that this deficiency might be one etiology of hereditary HCM.

Adult↗