CD36 mRNA Levels Research Articles

Neuronal growth regulator 1 promotes adipocyte lipid trafficking via interaction with CD36

Neuronal growth regulator 1 (NEGR1) is a glycosylphosphatidylinositol-anchored membrane protein associated with several human pathologies, including obesity, depression, and autism. Recently, significantly enlarged white adipose tissue, hepatic lipid accumulation, and decreased muscle capacity were reported in Negr1-deficient mice. However, the mechanism behind these phenotypes was not clear. In the present study, we found NEGR1 to interact with cluster of differentiation 36 (CD36), the major fatty acid translocase in the plasma membrane. Binding assays with a soluble form of NEGR1 and in situ proximal ligation assays indicated that NEGR1-CD36 interaction occurs at the outer leaflet of the cell membrane. Furthermore, we show that NEGR1 overexpression induced CD36 protein destabilization in vitro. Both mRNA and protein levels of CD36 were significantly elevated in the white adipose tissue and liver tissues of Negr1−/− mice. Accordingly, fatty acid uptake rate increased in NEGR1-deficient primary adipocytes. Finally, we demonstrated that Negr1−/− mouse embryonic fibroblasts showed elevated reactive oxygen species levels and decreased adenosine monophosphate-activated protein kinase activation compared with control mouse embryonic fibroblasts. Based on these results, we propose that NEGR1 regulates cellular fat content by controlling the expression of CD36.

The Effects of Dexamethasone Treatment and Dietary Fat Composition on Liver Lipid Metabolism in Mice Consuming High Fat Diets

Omega‐3 fatty acids are essential fats that the body cannot produce on its own and play a very integral role in the body in regard to inflammation and hormone production. Glucocorticoids are hormones that are also effective in inflammation reduction and suppressing the immune system; however, often have many detrimental side effects such as adipose accumulation, muscle atrophy and metabolic dysfunction. The purpose of this research experiment was to examine the effects dexamethasone treatment in combination with diets high in either omega‐3 fatty acids or omega‐6 fatty acids on markers of lipid metabolism in the liver. For a span of 4 weeks, two groups of mice were placed on a diet consisting of 45% fat containing either high omega‐3 or omega‐6 fatty acids. On the fifth week mice were randomized to two groups per diet and received either PBS placebo or Dexamethasone (Dex) injections daily. We hypothesized that Dex treatment would induce liver lipid accumulation and an omega‐3 rich diet would prevent this. At the completion of the 5 weeks, tissue was harvested and liver triglycerides were measured. There was a main effect of omega‐3 diet to have lower liver triglyceride levels (p=0.01). Fasn, Crat, Hsl, Cd36, and Fabp mRNA levels were measured in liver tissue. The resulted show that CratmRNA (p=.0153) and HslmRNA (p=.0417) was increased with omega‐3 rich diet, but there was no effect of Dex treatment. The Cd36 (p=.0495) and Fabp(p=.0229) mRNA increased in omega‐6 rich diets treated with Dex and omega‐3 high fat diet attenuated this increase. It can be concluded that one week of Dexamethasone treatment altered liver lipid signaling primarily by increasing lipid import and transport regulators, and omega‐3 high fat diet was able to prevent this increase. Additionally, omega‐3 high fat diet increase markers of lipid metabolism that were unaltered with one week of dex. These data suggest that omega‐3 fatty acids may help prevent the detrimental side effects of glucocorticoid treatment.

The upregulation of circFNDC3B aggravates the recurrence after endoscopic submucosal dissection (ESD) in early gastric cancer (EGC) patients

It has been reported that the expression of CD44 variant 9 could be utilized as a predictive marker for the recurrence in early gastric cancer (EGC) after endoscopic submucosal dissection (ESD). And circFNDC3B was proved to increase the migration and invasion of gastric cancer (GC) cells. In this study, we recruited 96 EGC patients after ESD treatment and grouped them into High circFNDC3B expression group (High expression group) and Low circFNDC3B expression group (Low expression group). Accordingly, we found that the recurrence-free rate in the High expression group was lower than that in the Low expression group. In the High expression group, the relative expression of miR-942 and miR-510 was both suppressed while the relative expression of CDH1 mRNA and CD44 mRNA/protein was increased compared with those in the Low expression group. CircFNDC3B was found to target miR-942 and miR-510 and suppress their expressions respectively. Moreover, miR-942 was found to target CD44 mRNA while miR-510 was found to target CDH1 mRNA. The overexpression of circFNDC3B led to the down-regulation of miR-942 and miR-510, which accordingly resulted in the up-regulation of CD44 and CDH1 in MKN28 cells. Moreover, we found H. pylori infection could promote the expression of circFNDC3B, which also resulted in up-regulated CD44 and CDH1 mRNA level in rTip-α cultivated MKN28 cells. In summary, our study demonstrated that a higher level of circFNDC3B could lead to the increased expression of CD44 and CDH1 via modulating the signaling pathways of miR-942/CD44 and miR-510/CDH1 in EGC patients. And the up-regulation of CD44 and CDH1 would accordingly result in a higher recurrence rate of EGC patients treated by ESD.

Decreased Ankyrin Expression Is Associated with Repressed eNOS Signaling, Cell Proliferation, and Osteogenic Differentiation in Osteonecrosis of the Femoral Head.

Reduced nitric oxide synthase (NOS) activity and decreased reparative potentials in stem cells may be involved in the pathogenesis of osteonecrosis of the femoral head (ONFH), but the underlying mechanism is not clear. Ankyrin, a cytoskeletal protein, can promote NOS expression and many cellular functions when it interacts with the CD44 receptors on the stem cells. This study investigated whether ankyrin is involved in the pathogenesis of ONFH. Bone marrow stem cells (BMSCs) from ONFH patients were compared with cells from patients with proximal femoral fracture and BMSC cell lines (PT-2501, Lonza, NC, USA). Differences in the expression levels and downstream signal pathway of ankyrin-Akt-eNOS in BMSCs were studied between ONFH and control. The involvement of ankyrin in the signal cascade, cell proliferation, and differentiation were further investigated by silencing ankyrin using small interfering (si)RNA. We found the basal mRNA levels of ankyrin and CD44 in BMSCs from the ONFH group were significantly lower as compared with those from the control group. The signal transduction of CD44-ankyrin-Akt-eNOS was significantly repressed in the ONFH group as compared with the control group after hyaluronic acid treatment. Knockdown of ankyrin by siRNA could attenuate the eNOS signaling as well as the BMSCs proliferation and osteogenic differentiation. The proliferation ability and osteogenic differentiation potential of the BMSCs from the ONFH group were significantly reduced as compared with the control group, but they can be enhanced to the baseline levels of the control group by hyaluronic acid treatment. The aberrant eNOS signaling, reduced cell proliferation, and osteogenic differentiation potential in BMSCs from ONFH patients are associated with the decreased ankyrin expression. Altered signal transduction, proliferation, and osteogenic differentiation ability in BMSCs may be involved in the pathogenesis of ONFH. These need further studies especially in BMSC-based cell therapy.

Tumor-associated macrophages and risk of recurrence in stage III colorectal cancer.

Tumor‐associated macrophages (TAMs) have a unique favorable effect on the prognosis of colorectal cancer (CRC), although their association with stage‐specific outcomes remains unclear. We assessed the densities of CD68+ and CD163+ TAMs at the invasive front of resected CRC stage III CRC from 236 patients, 165 of whom received post‐surgical FOLFOX treatment, and their relationship with disease‐free survival (DFS). Associations between macrophage mRNAs and clinical outcome were investigated in silico in 59 stage III CRC and FOLFOX‐treated patients from The Cancer Genome Atlas (TCGA). Biological interactions of SW480 and HT29 cells and macrophages with FOLFOX were tested in co‐culture models. Low TAM densities were associated with shorter DFS among patients receiving FOLFOX (CD68+, p = 0.0001; CD163+, p = 0.0008) but not among those who were untreated. By multivariate Cox analysis, only low TAM (CD68+, p = 0.001; CD163+, p = 0.002) and nodal status (CD68+, p = 0.009; CD163+, p = 0.007) maintained an independent predictive value. In the TCGA cohort, high CD68 mRNA levels were associated with better outcome (p = 0.02). Macrophages enhanced FOLFOX cytotoxicity on CRC cells (p < 0.01), and drugs oriented macrophage polarization from M2‐ to M1‐phenotype. Low TAM densities identify stage III CRC patients at higher risk of recurrence after adjuvant therapy, and macrophages can augment the chemo‐sensitivity of micro‐metastases.

Transcript levels in plasma contribute substantial predictive value as potential Alzheimer's disease biomarkers in African Americans.

SummaryBackgroundAfrican Americans (AA) remain underrepresented in Alzheimer's disease (AD) research, despite the prevalence of AD being double in AA compared to non-Hispanic whites. To address this disparity, our group has established the Florida Consortium for African American Alzheimer's Disease Studies (FCA3DS), focusing on the identification of genetic risk factors and novel plasma biomarkers.MethodUtilizing FCA3DS whole exome sequence (WES) and plasma RNA samples from AD cases (n=151) and cognitively unimpaired (CU) elderly controls (n=269), we have performed differential gene expression (DGE) and expression quantitative trait locus (eQTL) analyses on 50 transcripts measured with a custom nanoString® panel. We designed this panel to measure, in plasma, cell-free mRNA (cf-mRNA) levels of AD-relevant genes.FindingsAssociation with higher plasma CLU in CU vs. AD remained significant after Bonferroni correction. Study-wide significant eQTL associations were observed with 105 WES variants in cis with 22 genes, including variants in genes previously associated with AD risk in AA such as ABCA7 and AKAP9. Results from this plasma eQTL analysis identified AD-risk variants in ABCA7 and AKAP9 that are significantly associated with lower and higher plasma mRNA levels of these genes, respectively. Receiver operating characteristic analysis of age, sex APOE-ε4 dosage, CLU, APP, CD14, ABCA7, AKAP9 and APOE mRNA levels, and ABCA7 and AKAP9 eQTLs, achieved 77% area under the curve to discriminate AD vs. CU, an 8% improvement over a model that only included age, sex and APOE-ε4 dosage.InterpretationIncorporating plasma mRNA levels could contribute to improved predictive value of AD biomarker panels.FundingThis work was supported by the National Institute on Aging [RF AG051504, U01 AG046139, R01 AG061796 to NET; P30 AG062677 to JAL and NGR]; Florida Health Ed and Ethel Moore Alzheimer's Disease grants [5AZ03 and 7AZ17 to NET; 7AZ07 to MMC; 8AZ08 to JAL].

TIM-3 gene is highly expressed in ephithelial ovarian cancer to promote proliferation and migration of ovarian cancer cells

To analyze the expression of immunoglobulin mucin molecule 3 (TIM-3) in epithelial ovarian cancer (EOC) and the effects of TIM-3 knockdown and overexpression on proliferation and migration of ovarian cancer cells. We analyzed TIM-3 expression in EOC and normal ovarian tissues using GEPIA database. We also detected TIM-3 expression levels in 82 surgical specimens of EOC and 18 specimens of normal ovarian tissues using immunohistochemistry, and analyzed the correlation of TIM-3 expression with clinicopathological parameters and survival outcomes of the patients. The expression of TIM-3 and Wnt1 mRNA in the tissues were detected using qRT-PCR. We constructed SKOV3 cell models of TIM-3 knockdown and overexpression and examined the changes in proliferation, apoptosis, migration and invasion of the cells using MTT assay, Annexin V-FITC/PI staining, scratch test and Transwell assay. The activity of Wnt/β-catenin pathway in the transfected was detected using dual luciferase reporter assay, and the mRNA levels of TCF-7, TCCFL-2 and CD44 were detected using qPCR. The protein expressions of MMP-9, CD44, Wnt1, β-catenin and E-cad in the transfected cells were detected with Western blotting. The positive expression rate of TIM-3 was significantly higher in EOC tissues than in normal ovarian tissues (P < 0.05). The expression of TIM-3 was significantly correlated with FIGO stage, histological differentiation and lymph node metastasis, and was positively correlated with Wnt1 level (P < 0.05). In SKOV3 cells, TIM-3 knockdown significantly lowered the activity of Wnt/ β-catenin pathway, inhibited cell proliferation, migration and invasion, and promoted cell apoptosis. TIM-3 knockdown significantly down-regulated the mRNA levels of TCF-7, TCFL-2 and CD44 and the protein levels of MMP-9, CD44, Wnt1 and β-catenin, and significantly up-regulated the expression level of E-cad (P < 0.05). Overexpression of TIM-3 caused opposite effects in SKOV3 cells. TIM-3 is highly expressed in EOC tissue to promote malignant behaviors of the tumor cells possibly by activating the Wnt/β-catenin signal pathway.

Abstract P2-13-12: High CD36 expression predicts worse event free survival in HER2-positive breast cancer patients treated with neoadjuvant trastuzumab-based therapy: An exploratory analysis of the NeoALTTO study

Abstract Background: Despite great efforts to identify tumor-related prognostic biomarkers in early-stage Human Epidermal growth factor Receptor 2 (HER2)-positive Breast Cancer (HER2+ BC), reliable determinants of long-term clinical outcomes are lacking. HER2+ BC is a lipogenic malignancy, and HER2-driven fatty acid (FA) biosynthesis plays a crucial role in sustaining cancer cell growth, proliferation, and metastatization. Recently, FA uptake, a process mediated by the transmembrane transporter CD36, has emerged as a new determinant of acquired resistance to anti-HER2 treatments in preclinical studies. Methods: The phase III NeoALTTO (NCT00553358) trial randomized 455 HER2+ BC patients to receive lapatinib, trastuzumab, or the combination of both drugs with weekly paclitaxel, followed by surgery, adjuvant fluorouracil, epirubicin, and cyclophosphamide and the same anti-HER2 therapy received before surgery. In the present analysis, we tested the hypothesis that higher intratumor CD36 mRNA levels could be associated with worse Event Free Survival (EFS) in a cohort of NeoALTTO patients for whom global gene expression analysis of baseline tumor samples through ClariomS platform was available. Results: A total of 180 patients were included (trastuzumab arm: n=66; lapatinib arm: n=65; combination arm: n=49). Higher baseline CD36 expression levels were associated with significantly worse EFS in patients treated with trastuzumab-based therapy, at both univariate (continuous scale, HR:1.73, 95% CI 1.20-2.49) and multivariable (HR:1.72, 95% CI 1.20-2.46) analysis, but not in patients treated with lapatinib- or trastuzumab plus lapatinib (HR:1.01; 95% CI: 0.69-1.47; p=0.98 and HR:1.02; 95% CI:0.54-1.95; p=0.94, respectively). CD36 levels did not predict pathological Complete Response (pCR) probability, while combining CD36 expression (based on median levels) with pCR status identified two subsets of patients with especially bad or good prognosis (7-year EFS rates in patients with high CD36/no pCR: 47%, 95% CIs: 0.26-0.66 vs. 79%, 95% CIs: 0.62-0.88 in patients with low CD36/any pCR status (Yes/No) OR high CD36/pCR; Log-Rank test p= 0.006). Conclusions: This is the first study to show that high CD36 expression is independently predictive of worse long-term clinical outcomes in HER2+ BC patients treated with neoadjuvant trastuzumab-based therapy. Along with recent preclinical data highlighting CD36 role in tumor resistance to anti-HER2 therapies, our findings point to CD36 as a novel promising target for HER2+ BC treatment. Citation Format: Francesca Ligorio, Serena Di Cosimo, Paolo Verderio, Chiara Maura Ciniselli, Sara Pizzamiglio, Lorenzo Castagnoli, Tiziana Triulzi, Elda Tagliabue, Sarra El-Abed, Miguel Izquierdo, Evandro de Azambuja, Paolo Nuciforo, Jens Huober, Luca Moscetti, Wolfgang Janni, M Coccia-Portugal, Paola Corsetto, Antonino Belfiore, Daniele Lorenzini, Maria Grazia Daidone, Andrea VIngiani, Serenella M Pupa, Giancarlo Pruneri, Claudio Vernieri. High CD36 expression predicts worse event free survival in HER2-positive breast cancer patients treated with neoadjuvant trastuzumab-based therapy: An exploratory analysis of the NeoALTTO study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-13-12.

P024 CD40 and key CD40/CD154 pathway members are significantly upregulated in inflamed lesional IBD biopsies as shown by whole transcriptome AmpliSeq gene expression profiling and corresponding immunohistochemistry

Abstract Background Inflammatory bowel diseases (IBDs) are chronic inflammatory disorders with growing evidence of a critical role of the CD40/CD40L pathway (Shenhaji et al Front Immunol 6:529). To confirm and extend these findings, we profiled colonic biopsies from IBD patients with active ulcerative colitis (UC) and Crohn’s disease (CD) as well as non-IBD controls (HV). Methods Mucosal inflamed and non-inflamed biopsies of IBD patients and of healthy control subjects were immediately immersed in RNAlater (for RNA) or formaldehyde (for histology). RNA was extracted by RNeasy (Qiagen) with DNase digestion, quantified by UV spectrophotometry, and quality-controlled by Bioanalyzer (Agilent). 10 ng total RNA was subjected to ultrahigh-multiplexed RT-PCR using the AmpliSeq Transcriptome Human Gene Expression kit for 20,802 genes (Thermo Fisher). Barcoded samples were multiplexed and amplicons sequenced on an Ion GeneStudio S5 (Thermo Fisher). The resulting Excel matrix of normalized reads [RPM = Reads Per Million mapped reads; equivalent to TPM, Transcripts Per Million] was analyzed by Qlucore Omics Explorer 3.7 (Qlucore) and GraphPad Prism 9 (GraphPad Software). For histology, 2 μm sections of FFPE colonic biopsies were subjected to standard hematoxylin and eosin stain, and to automated immunohistochemistry (IHC; Ventana Discovery XT &amp; Leica BOND RX) using standard cell-type specific antibodies and anti-CD40 Ab213205 (Abcam) and anti-CD40L AF617 (R&amp;D Systems). Results 161 colonic biopsies were analyzed from 36 CD and 26 UC patients (from inflamed and non-inflamed mucosa per subject), and 14 HV. Unbiased gene expression analysis by principal component analysis and hierarchical clustering showed upregulation of known inflammation markers and inflammasome components. In inflamed mucosa mRNA levels of CD40 (figure), CD154, CD44, CD86, KYNU, FCRL4, and others revealed a significant consistent upregulation of the CD40/CD154 pathway. Representative corresponding IHC stainings confirmed the upregulation of CD40 and CD154 at the protein level showing strong expression of CD40 in lesional biopsies (inflamed areas and epithelial cells), moderate expression in non-lesional and low in HV biopsies (no expression in epithelial cells), while higher expression of CD154 was observed in lesional and non-lesional biopsies compared to HV. Conclusion Consistent upregulation and activation of the CD40/CD154 axis was observed in inflamed mucosa of patients with IBD. Together with other (pre-)clinical evidence pointing to the importance of CD40 signaling, manipulation of this pathway might be a potential therapeutic target in IBD.

Eukaryotic elongation factor 2 kinase regulates foam cell formation via translation of CD36.

Eukaryotic elongation factor 2kinase (eEF2K) is an atypical protein kinase that controls protein synthesis in cells under stress. Although well studied in cancer, less is known about its roles in chronic inflammatory diseases. Here, we examined its regulation of macrophage cholesterol handling in the context of atherosclerosis. eEF2K mRNA expression and protein activity were upregulated in murine bone marrow-derived macrophages (BMDMs) exposed to oxidized low-density lipoprotein cholesterol (oxLDL). When incubated with oxLDL, BMDMs from eEF2K knockout (Eef2k-/- ) mice formed fewer Oil Red O+ foam cells than Eef2k+/+ BMDMs (12.5%±2.3% vs. 32.3%±2.0%, p<.01). Treatment with a selective eEF2K inhibitor, JAN-384, also decreased foam cell formation for C57BL/6J BMDMs and human monocyte-derived macrophages. Disabling eEF2K selectively decreased protein expression of the CD36 cholesterol uptake receptor, mediated by a reduction in the proportion of translationally active Cd36mRNA. Eef2k-/- mice bred onto the Ldlr-/- background developed aortic sinus atherosclerotic plaques that were 30% smaller than Eef2k+/+ -Ldlr-/- mice after 16weeks of high cholesterol diet (p<.05). Although accompanied by a reduction in plaque CD36+ staining (p<.05) and lower CD36 expression in circulating monocytes (p<.01), this was not associated with reduced lipid content in plaques as measured by oil red O staining. Finally, EEF2K and CD36mRNA levels were higher in blood mononuclear cells from patients with coronary artery disease and recent myocardial infarction compared to healthy controls without coronary artery disease. These results reveal a new role for eEF2K in translationally regulating CD36 expression and foam cell formation in macrophages. Further studies are required to explore therapeutic targeting of eEF2K in atherosclerosis.

Carotenoid transporter CD36 expression depends on hypoxia-inducible factor-1α in mouse soleus muscles.

Dietary β-carotene induces muscle hypertrophy and prevents muscle atrophy in red slow-twitch soleus muscles, but not in white fast-twitch extensor digitorum longus (EDL) muscles and gastrocnemius muscles. However, it remains unclear why these beneficial effects of β-carotene are elicited in soleus muscles. To address this issue, we focused on carotenoid transporters in skeletal muscles. In mice, Cd36 mRNA levels were higher in red muscle than in white muscle. The siRNA-mediated knockdown of CD36 decreased β-carotene uptake in C2C12 myotubes. In soleus muscles, CD36 knockdown inhibited β-carotene-induced increase in muscle mass. Intravenous injection of the hypoxia marker pimonidazole produced more pimonidazole-bound proteins in soleus muscles than in EDL muscles, and the hypoxia-inducible factor-1 (HIF-1) α protein level was higher in soleus muscles than in EDL muscles. In C2C12 myotubes, hypoxia increased the expression of CD36 and HIF-1α at the protein and mRNA levels, and HIF-1α knockdown reduced hypoxia-induced increase in Cd36 mRNA level. In soleus muscles, HIF-1α knockdown reduced Cd36 mRNA level. These results indicate that CD36 is predominantly involved in β-carotene-induced increase in soleus muscle mass of mice. Furthermore, we demonstrate that CD36 expression depends on HIF-1α in the soleus muscles of mice, even under normal physiological conditions.

Opium may affect coronary artery disease by inducing inflammation but not through the expression of CD9, CD36, and CD68

The molecular mechanisms of opium with regard to coronary artery disease (CAD) have not yet been determined. The aim of the present study was to evaluate the effect of opium...

Characterization of Total RNA, CD44, FASN, and PTEN mRNAs from Extracellular Vesicles as Biomarkers in Gastric Cancer Patients.

Simple SummaryLiquid biopsy is an easily accessible and non-invasive method to gain information about tumor diseases. The purpose of our study was to determine the value of extracellular vesicle-derived mRNAs as biomarkers for the diagnosis of gastric cancer and the response to its treatment. In a cohort of 87 gastric cancer patients and a control group of 14 individuals, we analyzed the absolute RNA concentration from extracellular vesicles (EV) and the relative levels of FASN, PTEN, and CD44 mRNA, and their correlation with clinico-pathological features. These correlated with treatment, tumor grading, and the pathological subtype according to Laurén’s classification. This might reflect their potential as both diagnostic and therapeutic predictors.In-depth characterization has introduced new molecular subtypes of gastric cancer (GC). To identify these, new approaches and techniques are required. Liquid biopsies are trendsetting and provide an easy and feasible method to identify and to monitor GC patients. In a prospective cohort of 87 GC patients, extracellular vesicles (EVs) were isolated from 250 µL of plasma. The total RNA was isolated with TRIZOL. The total RNA amount and the relative mRNA levels of CD44, PTEN, and FASN were measured by qRT-PCR. The isolation of EVs and their contained mRNA was possible in all 87 samples investigated. The relative mRNA levels of PTEN were higher in patients already treated by chemotherapy than in chemo-naïve patients. In patients who had undergone neoadjuvant chemotherapy followed by gastrectomy, a decrease in the total RNA amount was observed after neoadjuvant chemotherapy and gastrectomy, while FASN and CD44 mRNA levels decreased only after gastrectomy. The amount of RNA and the relative mRNA levels of FASN and CD44 in EVs were affected more significantly by chemotherapy and gastrectomy than by chemotherapy alone. Therefore, they are a potential biomarker for monitoring treatment response. Future analyses are needed to identify GC-specific key RNAs in EVs, which could be used for the diagnosis of gastric cancer patients in order to determine their molecular subtype and to accompany the therapeutic response.

Hyperglycemia-induced effects on glycocalyx components in the retina

PurposeDiabetic retinopathy is a vision-threatening complication of diabetes characterized by endothelial injury and vascular dysfunction. The loss of the endothelial glycocalyx, a dynamic layer lining all endothelial cells, contributes to several microvascular pathologies, including an increase in vascular permeability, leukocyte plugging, and capillary occlusion, and may drive the progression of retinopathy. Previously, a significant decrease in glycocalyx thickness has been observed in diabetic retinas. However, the effects of diabetes on specific components of the retinal glycocalyx have not yet been studied. Therefore, the aim of our study was to investigate changes in synthesis, expression, and shedding of retinal glycocalyx components induced by hyperglycemia, which could provide a novel therapeutic target for diabetic retinopathy. MethodsPrimary rat retinal microvascular endothelial cells (RRMECs) were grown under normal glucose (5 mM) or high-glucose (25 mM) conditions for 6 days. The mRNA and protein levels of the glycocalyx components were examined using qRT-PCR and Western blot analysis, respectively. Further, mass spectrometry was used to analyze protein intensities of core proteins. In addition, the streptozotocin-induced Type 1 diabetic rat model was used to study changes in the expression of the retinal glycocalyx in vivo. The shedding of the glycocalyx was studied in both culture medium and in plasma using Western blot analysis. ResultsA significant increase in the shedding of syndecan-1 and CD44 was observed both in vitro and in vivo under high-glucose conditions. The mRNA levels of syndecan-3 were significantly lower in the RRMECs grown under high glucose conditions, whereas those of syndecan-1, syndecan-2, syndecan-4, glypican-1, glypican-3, and CD44 were significantly higher. The protein expression of syndecan-3 and glypican-1 in RRMECs was reduced considerably following exposure to high glucose, whereas that of syndecan-1 and CD44 increased significantly. In addition, mass spectrometry data also suggests a significant increase in syndecan-4 and a significant decrease in glypican-3 protein levels with high glucose stimulation. In vivo, our data also suggest a significant decrease in the mRNA transcripts of syndecan-3 and an increase in mRNA levels of glypican-1 and CD44 in the retinas of diabetic rats. The diabetic rats exhibited a significant reduction in the retinal expression of syndecan-3 and CD44. However, the expression of syndecan-1 and glypican-1 increased significantly in the diabetic retina. ConclusionsOne of the main findings of our study was the considerable diversity of glucose-induced changes in expression and shedding of various components of endothelial glycocalyx, for example, increased endothelial and retinal syndecan-1, but decreased endothelial and retinal syndecan-3. This indicates that the reported decrease in the retinal glycocalyx in diabetes in not a result of a non-specific shedding mechanism. Moreover, mRNA measurements indicated a similar diversity, with increases in endothelial and/or retinal levels of syndecan-1, glypican-1, and CD44, but a decrease for syndecan-3, with these increases in mRNA potentially a compensatory reaction to the overall loss of glycocalyx.

Gene Expression Patterns and Functional Characterization of CD36 in Normal Hematopoietic Cells

Metabolic reprogramming is a hallmark of cancer development and progression. Lipid metabolism is among the most deregulated metabolic pathways in cancer contributing to cell survival and invasion. The fatty acid translocase CD36 has attracted attention in cancer research in recent years due to its role in fatty acid transport as a scavenger receptor. We have recently reported that upregulated APOC2 cooperates with CD36 contributing to leukemia growth by promoting the LYN-ERK signaling mediated metabolic activities of acute myeloid leukemia (AML) cells. Consistently, the knockdown of CD36 or treatment with anti-CD36 antibody reduced the leukemia progression and promoted the overall survival of AML xenograft mice. CD36 is also present on various types of normal cells, including monocytes, macrophages, endothelial cells, adipocytes, and platelets and contribute to their normal functions. Thus, whether targeting CD36 in normal hematopoietic cells poses any toxicity warrants investigation to bring the therapeutic strategy of targeting CD36 in AML to maturity. Here, we leveraged public data to assess the expression patterns of CD36 in normal hematopoietic cells. We found that CD36 expression is several folds higher in dendritic cells, monocytes, and NK cells compared with B cells, eosinophils, neutrophils, and T cells (ANOVA P < 0.001). To investigate the role of Cd36 in normal hematopoietic cells, we carried out gain- and loss-of-function approaches in murine normal hematopoietic primary cells. We engineered a tet-on inducible shRNA lentiviral plasmid targeting two different sequences of the mouse Cd36. In both healthy mouse primary spleen and bone marrow cells, the two pairs of shRNAs reduced the Cd36 mRNA levels compared with scramble control group (~70-90% reduction in mRNA expression). We also engineered two different lentivirus ectopic expression plasmid to overexpress murine Cd36 (PLVX-Cd36 virus and PCDH-Cd36). Lentiviral transduction of both spleen and bone marrow mouse cells confirmed by microscopy visualization of GFP-expressing cells showed several folds increase in Cd36 expression for both plasmids measured by qPCR and western blot. We assessed the effect of Cd36 knockdown on the expansion of spleen and bone marrow hematopoietic cells over five days of cell culture. Relative to the 1 st day of cell count, there was no significant decrease in the mean bone marrow cell and spleen count between the two pair of shRNA compared with scramble control group at day 3 and day 5 post doxycycline treatment (P > 0.05). Cells in the different groups showed about 2 folds expansion on day 5 relative to day 1. Our preliminary data suggest that Cd36 knockdown has limited impact on the survival of normal hematopoietic cells. In vivo experiments assessing the effect of Cd36 gain and loss of function on the engraftment of normal hematopoietic cells in mice are ongoing to further establish the functional impact of Cd36 manipulation on normal hematopoietic cells. Altogether, our studies will demonstrate whether CD36 is dispensable for the survival of normal hematopoietic cells and thus may potentially present a viable therapeutic approach in AML. DisclosuresYaghmour: Jazz: Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Astellas: Speakers Bureau; Alexion: Speakers Bureau; BMS: Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Agios: Consultancy, Speakers Bureau.

Transcript Levels in Plasma Contribute Substantial Predictive Value as Potential Alzheimer's Disease Biomarkers in African Americans

Background: African Americans (AA) remain underrepresented in Alzheimer’s disease (AD) research, despite the prevalence of AD being double in AA compared to non-Hispanic whites. To address this disparity, our group has established the Florida Consortium for African American Alzheimer’s Disease Studies (FCA3DS), focusing on the identification of genetic risk factors and novel plasma biomarkers. Method: Utilizing FCA 3 DS whole exome sequence (WES) and plasma RNA samples from AD cases (n=151) and cognitively unimpaired (CU) elderly controls (n=269), we have performed differential gene expression (DGE) and expression quantitative trait locus (eQTL) analyses on 50 transcripts measured with a custom nanoString® panel. We designed this panel to measure, in plasma, cell-free mRNA (cf-mRNA) levels of AD-relevant genes. Findings: Association with higher plasma CLU in CU vs. AD remained significant after Bonferroni correction. Study-wide significant eQTL associations were observed with 105 WES variants in cis with 22 genes, including variants in genes previously associated with AD risk in AA such as ABCA7 and AKAP9. Results from this plasma eQTL analysis identified AD-risk variants in ABCA7 and AKAP9 that are significantly associated with lower and higher plasma mRNA levels of these genes, respectively. ROC analysis of age, sex APOE-e4 dosage, CLU, APP, CD14, ABCA7, AKAP9 and APOE mRNA levels, and ABCA7 and AKAP9 eQTLs, achieved 77% AUC to discriminate AD vs. CU, an 8% improvement over a model that only included age, sex and APOE-e4 dosage. Interpretation: Incorporating plasma mRNA levels could contribute to improved predictive value of AD biomarker panels. Funding: National Institute on Aging, Florida Health Ed and Ethel Moore Alzheimer’s Disease grants. Declaration of Interest: None to declare. Ethical Approval: Informed consent and approval by the Mayo Clinic Institutional Review Board was obtained.

Identifying the Main Functional Pathways Associated with Cognitive Resilience to Alzheimer's Disease.

Understanding the mechanisms involved in cognitive resilience in Alzheimer’s disease (AD) represents a promising strategy to identify novel treatments for dementia in AD. Previous findings from our group revealed that the study of aged-Tg2576 cognitive resilient individuals is a suitable tool for this purpose. In the present study, we performed a transcriptomic analysis using the prefrontal cortex of demented and resilient Tg2576 transgenic AD mice. We have been able to hypothesize that pathways involved in inflammation, amyloid degradation, memory function, and neurotransmission may be playing a role on cognitive resilience in AD. Intriguingly, the results obtained in this study are suggestive of a reduction of the influx of peripheral immune cells into the brain on cognitive resilient subjects. Indeed, CD4 mRNA expression is significantly reduced on Tg2576 mice with cognitive resilience. For further validation of this result, we analyzed CD4 expression in human AD samples, including temporal cortex and peripheral blood mononuclear cells (PBMC). Interestingly, we have found a negative correlation between CD4 mRNA levels in the periphery and the score in the Mini-Mental State Exam of AD patients. These findings highlight the importance of understanding the role of the immune system on the development of neurodegenerative diseases and points out to the infiltration of CD4+ cells in the brain as a key player of cognitive dysfunction in AD.

Precision Medicine in Graves' Disease: CD40 Gene Variants Predict Clinical Response to an Anti-CD40 Monoclonal Antibody.

BackgroundCD40, a key co-stimulatory molecule expressed on antigen-presenting cells, is genetically associated with a number of autoimmune diseases including Graves’ disease (GD). Therefore, recent therapies targeting CD40 have been developed, including the anti-CD40 monoclonal antibody Iscalimab. In a recent pilot study, Iscalimab was shown to induce clinical remission in ~ 50% of GD patients, but the reason why only 50% of GD patients responded is not known. The aim of our study was to test the hypothesis that specific CD40 single nucleotide polymorphism (SNP) genotypes and haplotypes are associated with clinical response of GD patients to Iscalimab.MethodsWe extracted genomic DNA from the whole blood of 13 GD patients treated with Iscalimab, and genotyped seven CD40 single nucleotide polymorphisms (SNPs) associated with autoimmunity. Additionally, we analyzed CD40 mRNA expression levels in whole blood. The patients’ CD40 SNP genotypes and mRNA levels were tested for association with clinical response to Iscalimab.ResultsThree common haplotypes, designated haplotypes A, B, and C, were identified. Haplotypes B and C were associated with higher CD40 mRNA levels and clinical response to Iscalimab (i.e., patients achieving euthyroidism without need for additional medications), while haplotype A was associated with decreased CD40 mRNA levels and no response to Iscalimab.ConclusionOur data suggest that genetic polymorphisms in the CD40 gene drive its expression levels and response to Iscalimab. Polymorphisms associated with higher CD40 levels are also associated with clinical response to CD40-targeted therapies. These results set the stage to implementing precision medicine in the therapeutic approach to GD.

The Role of CD40 in Allergic Rhinitis and Airway Remodelling.

Background Allergic rhinitis (AR) affects millions of people and is lack of effective treatment. CD40 is an important costimulatory molecule in immunity. However, few studies have focused on the role of CD40 in AR. Methods In this study, we built mouse model of chronic AR. The mice were divided into the AR, control, intravenous CD40 siRNA, and nasal CD40 siRNA groups (n = 6 each). We detected OVA-sIgE, IL-4, IL-5, IL-13, IL-10, IFN-γ, and TGF-β levels in serum and supernatant by ELISA, CD40+ splenic DCs, and Foxp3+ Tregs by flow cytometry and CD40 mRNA by RT2-PCR. We also used PAS and MT stains to assess tissue remodelling. Results (1) The OVA-sIgE, IL-4, IL-5, and IL-13 levels in the serum or supernatant of nasal septal membrane of AR mice were significantly higher than control. After treated with CD40 siRNA, those indicators were significantly decreased. The IFN-γ, IL-10, and TGF-β levels in AR mice were significantly lower than that in control and were increased by administration of CD40 siRNA. (2) AR mice had significantly fewer Foxp3+ Tregs in the spleen than control mice. After treated with CD40 siRNA, AR mice had significantly more Foxp3+ Tregs. (3) AR mice exhibited a significantly higher CD40 mRNA levels than control. Administration of CD40 siRNA significantly reduced the CD40 mRNA level. (4) The AR mice showed significantly greater collagen deposition than the control in MT staining. Applications of CD40 siRNA significantly reduced the collagen deposition in AR mice. Conclusion CD40 siRNA therapy shows promise for chronic AR as it significantly attenuated allergic symptoms and Th2-related inflammation and upregulated Foxp3+ Tregs. CD40 plays a role in tissue remodelling in AR, which can be inhibited by CD40 siRNA application.

MRNA expression analysis confirms CD44 splicing impairment in systemic lupus erythematosus patients.

Systemic Lupus Erythematosus (SLE) is a complex chronic autoimmune disease characterized by several immunological alterations. T cells have a peculiar role in SLE pathogenesis, moving from the bloodstream to the peripheral tissues, causing organ damage. This process is possible for their increased adherence and migration capacity mediated by adhesion molecules, such as CD44. Ten different variant isoforms of this molecule have been described, and two of them, CD44v3 and CD44v6 have been found to be increased on SLE T cells compared to healthy controls, being proposed as biomarkers of disease and disease activity. The process of alternative splicing of CD44 transcripts is not fully understood. We investigated the mRNA expression of CD44v3 and CD44v6 and also analyzed possible CD44 splicing regulators (ESRP1 molecule and rs9666607 CD44 polymorphism) in a cohort of SLE patients compared to healthy controls. This study involved 18 SLE patients and 18 healthy controls. Total RNA and DNA were extracted by peripheral blood mononuclear cells. The expression study was conducted by quantitative RT-polymerase chain reaction, using SYBR Green protocol. Genotyping of rs9666607 SNP was performed by direct sequencing. CD44v6 mRNA expression was higher in SLE patients compared to healthy controls (p = 0.028). CD44v3/v6 mRNA ratio in healthy controls was strongly unbalanced towards isoform v3 compared to SLE patients (p = 0.002) and decreased progressively from healthy controls to the SLE patients in remission and those with active disease (p = 0.015). The expression levels of CD44v3 and CD44v6 mRNA correlated with the disease duration (p = 0.038, Pearson r = 0.493 and p = 0.038, Pearson r = 0.495, respectively). Splicing regulator ESRP1 expression positively correlated with CD44v6 expression in healthy controls (p = 0.02, Pearson r = 0.532) but not in SLE patients. The variant A allele of rs9666607 of CD44 was associated with higher level of global CD44 mRNA (p = 0.04) but not with the variant isoforms. In SLE patients, the increase in CD44v6 protein correlates with a higher transcript level of this isoform, confirming an impairment of CD44 splicing in the disease, whose regulatory mechanisms require further investigation.