👤 Maan Khatib

Atherosclerotic cardiovascular disease (CVD) remains a leading cause of vascular disease worldwide. Atherosclerosis is characterized by the accumulation of lipids and oxidized lipids on the blood vessel walls. Coronary artery disease (CAD) is the most common display of atherosclerotic CVD. We investigated the effects of the bioactive lipids as lyso-diacylglyceryltrimethylhomoserine (lyso-DGTS (20,5,0)) and its derivative oleoyl-N-trimethyl homoserine amide (oleoyl amide-MHS) on the properties and functionality of HDL and paraoxonase 1 (PON1) activities in the serum of individuals who exhibited arterial plaque as observed by coronary CT angiography (CCTA). The study included two independent groups comprising 40 patients who had undergone arterial CCTA scans at Ziv Medical Center for various medical indications. The CAD group included 20 patients with coronary artery plaques with luminal stenosis of more than 50 % in a major coronary vessel. The control group consisted of 20 healthy patients (patients without artery plaques). Serum samples from CAD patients exhibited lower serum PON1 and cholesterol efflux activities and higher pro-inflammatory than the control group. HDL isolated from CAD patients contains elevated levels of oxidizing lipids (specifically lyso- phosphatidyl ethanolamines and lyso-phosphocholines(compared to the control. However, incubation of the CAD patients' serum with lyso-DGTS and oleoyl amide-MHS restored the antiatherogenic activities of HDL. The lipids increased serum PON1 activities, enhanced apoB-depleted serum cholesterol-efflux activity, and elevated the serum's anti-inflammatory properties. The results of the present study suggest the potential of the bioactive lipids lyso-DGTS and oleoyl amide-MHS to attenuate atherosclerosis via the improvement of dysfunctional HDL properties and PON1 activities. Further, in-vivo experiments are needed to assess the athero-protective effect of the lipids. Show less

The epithelial-mesenchymal transition (EMT) program is crucial for transforming carcinoma cells into a partially mesenchymal state, enhancing their chemoresistance, migration, and metastasis. This shift in cell state is tightly regulated by cellular mechanisms that are not yet fully characterized. One intriguing EMT aspect is the rewiring of the proteoglycan landscape, particularly the induction of heparan sulfate proteoglycan (HSPG) biosynthesis. This proteoglycan functions as a co-receptor that accelerates cancer-associated signaling pathways through its negatively-charged residues. However, the precise mechanisms through which EMT governs HSPG biosynthesis and its role in cancer cell plasticity remain elusive. Here, we identified exostosin glycosyltransferase 1 (EXT1), a central enzyme in HSPG biosynthesis, to be selectively upregulated in aggressive tumor subtypes and cancer cell lines, and to function as a key player in breast cancer aggressiveness. Notably, ectopic expression of EXT1 in epithelial cells is sufficient to induce HSPG levels and the expression of known mesenchymal markers, subsequently enhancing EMT features, including cell migration, invasion, and tumor formation. Additionally, EXT1 loss in MDA-MB-231 cells inhibits their aggressiveness-associated traits such as migration, chemoresistance, tumor formation, and metastasis. Our findings reveal that EXT1, through its role in HSPG biosynthesis, governs signal transducer and activator of transcription 3 (STAT3) signaling, a known regulator of cancer cell aggressiveness. Collectively, we present the EXT1/HSPG/STAT3 axis as a central regulator of cancer cell plasticity that directly links proteoglycan synthesis to oncogenic signaling pathways. Show less

Clear cell renal cell carcinomas (ccRCC) represent about 80% of the malignant neoplasia with this localization. Snail, Twist1 and Slug are transcription factors and play a central role in the epithelial-mesenchymal transition (EMT), which is involved in the progression of renal cell carcinoma (RCC). In this study, we analyzed the immunoexpression of these transcription factors in 50 cases of ccRCC, in relation to histopathological aggressiveness parameters of the lesions. The results indicated the association of Snail and Twist1 expression with high Fuhrman grade, as well as the association of Slug expression with low Fuhrman grade. The immunoexpression of Snail and Twist1 was significantly superior for advanced stages and Slug was overexpressed in early stages of ccRCC. Our study supports the usefulness of the Snail, Twist1 and Slug expression for the appreciation of aggressiveness in ccRCC, the panel being attractive for targeted therapy. Show less

Apolipoprotein A5 (apoA5) is a potent regulator of triglyceride (TG) metabolism and therefore may contribute to the pathogenesis of non-alcoholic fatty liver disease (NAFLD), a disease characterised by excessive TG-rich lipid droplets in hepatocytes. To test this hypothesis, we examined the mRNA expression of apoA5 in paediatric NAFLD livers in comparison to healthy controls. According to microarray and quantitative real-time PCR, human NAFLD livers exhibited elevated apoA5 expression compared to healthy controls. The apoA5 expression levels were positively correlated with hepatic TG storage and a marker for lipid droplets (perilipin), but were not correlated with plasma TG levels. These observations were confirmed with a NAFLD rat model. Interestingly, apoA5 expression was not altered in cultured fat-laden HepG2 cells, demonstrating that fat storage does not induce apoA5 in NAFLD livers. Therefore, the correlation between apoA5 and intracellular fat storage is likely explained by the potent effect of apoA5 in promoting intracellular fat storage. Our NAFLD patients and rats had elevated insulin resistance, which may have a role in elevating apoA5 expression in NAFLD livers. Our data support the hypothesis that apoA5 promotes hepatic TG storage and therefore contributes to the pathogenesis of NAFLD, and may represent a potential target for therapeutic intervention. Show less