👤 Rafael Rosell

Through GWAS studies we identified PATJ associated with functional outcome after ischemic stroke (IS). The aim of this study was to determine PATJ role in brain endothelial cells (ECs) in the context of stroke outcome. PATJ expression analyses in patient's blood revealed that: (i) the risk allele of rs76221407 induces higher expression of PATJ, (ii) PATJ is downregulated 24 h after IS, and (iii) its expression is significantly lower in those patients with functional independence, measured at 3 months with the modified Rankin scale ((mRS) ≤2), compared to those patients with marked disability (mRS = 4-5). In mice brains, PATJ was also downregulated in the injured hemisphere at 48 h after ischemia. Oxygen-glucose deprivation and hypoxia-dependent of Hypoxia Inducible Factor-1α also caused PATJ depletion in ECs. To study the effects of PATJ downregulation, we generated PATJ-knockdown human microvascular ECs. Their transcriptomic profile evidenced a complex cell reprogramming involving Notch, TGF-ß, PI3K/Akt, and Hippo signaling that translates in morphological and functional changes compatible with endothelial to mesenchymal transition (EndMT). PATJ depletion caused loss of cell-cell adhesion, upregulation of metalloproteases, actin cytoskeleton remodeling, cytoplasmic accumulation of the signal transducer C-terminal transmembrane Mucin 1 (MUC1-C) and downregulation of Notch and Hippo signaling. The EndMT phenotype of PATJ-depleted cells was associated with the nuclear recruitment of MUC1-C, YAP/TAZ, β-catenin, and ZEB1. Our results suggest that PATJ downregulation 24 h after IS promotes EndMT, an initial step prior to secondary activation of a pro-angiogenic program. This effect is associated with functional independence suggesting that activation of EndMT shortly after stroke onset is beneficial for stroke recovery. Show less

One strategy for combating cancer-drug resistance is to deploy rational polytherapy up front that suppresses the survival and emergence of resistant tumor cells. Here we demonstrate in models of lung adenocarcinoma harboring the oncogenic fusion of ALK and EML4 that the GTPase RAS-mitogen-activated protein kinase (MAPK) pathway, but not other known ALK effectors, is required for tumor-cell survival. EML4-ALK activated RAS-MAPK signaling by engaging all three major RAS isoforms through the HELP domain of EML4. Reactivation of the MAPK pathway via either a gain in the number of copies of the gene encoding wild-type K-RAS (KRAS(WT)) or decreased expression of the MAPK phosphatase DUSP6 promoted resistance to ALK inhibitors in vitro, and each was associated with resistance to ALK inhibitors in individuals with EML4-ALK-positive lung adenocarcinoma. Upfront inhibition of both ALK and the kinase MEK enhanced both the magnitude and duration of the initial response in preclinical models of EML4-ALK lung adenocarcinoma. Our findings identify RAS-MAPK dependence as a hallmark of EML4-ALK lung adenocarcinoma and provide a rationale for the upfront inhibition of both ALK and MEK to forestall resistance and improve patient outcomes. Show less

There is increasing evidence that suggests that particular histopathologic types of non-small-cell lung cancer (NSCLC) display distinct molecular characteristics. We analyzed, in lung squamous cell carcinoma (SCC) and adenocarcinoma (AC), the expression of 8 genes that constitute 2 previously reported prognostic expression signatures in NSCLC. Fresh-frozen tumor and normal lung samples were obtained at surgery from 135 patients with stage I-III NSCLC (89 (65.9%) SCC, 46 (34.1%) AC). Expression of CSF1 (colony stimulating factor for macrophages), carbonic anhydrase 9 (CA9), epithelial growth factor receptor (EGFR), dual specificity phosphatase 6 (DUSP6), v-erb-b2 erythroblastic leukemia viral oncogene homolog 3 (ERBB3), monocyte to macrophage differentiation-associated (MMD), lymphocyte-specific protein tyrosine kinase (LCK) and signal transducer and activator of transcription 1 (STAT1) was assessed in SCC, AC, and in normal lung by quantitative reverse transcriptase - polymerase chain reaction (qRT-PCR). Metastasis-free survival was analyzed according to the median value of gene expression in the entire NSCLC cohort and separately in SCC and AC. Expression of CA9, CSF1, DUSP6, STAT1, and MMD differed between NSCLC and normal lung. EGFR was more abundant in SCC compared with AC, whereas the reverse was true for DUSP6 and ERBB3. A high expression of CSF1 correlated with shorter metastasis-free survival in the entire NSCLC group (P = .016) and in SCC (P = .049) and AC (P = .034) cohorts. Several genes considered prognostic in NSCLC showed significantly different expression in SCC and AC, and thus should be analyzed separately in these 2 subtypes for their prognostic significance. CSF1 is similarly expressed in SCC and AC, and portends a poor outcome in the entire group of patients with NSCLC, and in SCC and AC when considered separately. Show less

Fatty acid desaturases introduce double bonds into growing fatty acid chains. The key desaturases in humans are Delta5-desaturase (D5D), Delta6-desaturase (D6D) and stearoyl-CoA desaturase (SCD). Animal and human data implicate hepatic desaturase activities in insulin resistance, obesity and dyslipidaemia. However, the role of desaturase activity in adipose tissue is uncertain. We therefore evaluated relationships between adipose mRNA expression, estimated desaturase activities (fatty acid ratios) in adipose tissue and insulin resistance. Subcutaneous adipose tissue mRNA expression of D5D (also known as FADS1), D6D (also known as FADS2) and SCD was determined in 75 individuals representative of the study population of 294 healthy 63-year-old men. Desaturation indexes (product/substrate fatty acid ratios) were generated from adipose tissue fatty acid composition in all individuals. Insulin resistance was defined as the upper quartile of the updated homeostasis model assessment (HOMA-2) index. The relevant desaturation indexes (16:1/16:0, 18:1/18:0, 20:4/20:3 and 18:3/18:2) reflected expression of SCD, but not of D5D or D6D in adipose tissue. Insulin-resistant individuals had a higher adipose tissue 18:1/18:0, but not 16:1/16:0 ratio than insulin-sensitive individuals. Individuals with a high adipose tissue 18:1/18:0 ratio were 4.4-fold (95% CI 1.8-11.8) more likely to be insulin resistant [threefold (95% CI 1.1-8.6) after adjustment for waist circumference and plasma triacylglycerol]. In a multiple regression model predicting HOMA-2, the independent effect of the 18:1/18:0 ratio was borderline (p=0.086). Adipose tissue desaturation indexes of SCD reflect the expression of the gene encoding the enzyme in this tissue. Elevated SCD activity within adipose tissue is closely coupled to the development of insulin resistance. Show less