👤 Alexandra Blanchard

CNS diseases are a prevailing cause of morbidity and mortality worldwide, and are influenced by environmental and biological factors, including genetic risk. Here, we generated genome-wide genetic data on a large cohort of brain tissue donors with in-depth clinical and neuropathological phenotyping, allowing for broad investigations into the risk and mechanisms of these neurological, neurodevelopmental, and psychiatric conditions. This resource consists of 9,663 donors with array-based genotyping and 9,543 donors with whole-genome sequencing completed. The clinical diagnoses of these donors include 148 central nervous system diseases clustered into 15 broad categories by International Classification of Diseases-10 (ICD-10) coding. These donors were collected by six repositories comprising the National Institutes of Health NeuroBioBank, with an average participant age of 60 years. While primarily older individuals of European descent, the cohort also contains younger donors and individuals from non-European backgrounds. Variants were detected in whole-genome sequencing (WGS), normalized and annotated to describe their functional impact, resulting in 171,121,209 unique variants and 1,078,774 non-silent variants. These raw and normalized data have been made available as a neurogenomics resource in the National Institute of Mental Health Data Archive (NIMH NDA) (nda.nih.gov), combined with donor-matched deep demographic and phenotypic data from the NeuroBioBank Portal (neurobiobank.nih.gov). To illustrate applications, we replicated the strong association observed in previous studies between pathogenic CAG nucleotide repeat expansions in the HTT gene with the clinical diagnosis of Huntington's disease, as well as associations of the APOE gene with Alzheimer's disease, and examined the association of polygenic risk scores with the three most common disease diagnoses in the cohort. Show less

The early phase of drug development relies on the examination of the efficacy and safety of therapeutic agents in animal models. Due to their close genetic and physiological relation to humans, cynomolgus monkeys ( Show less

Glioblastoma (GBM) is a highly lethal type of cancer. GBM recurrence following chemoradiation is typically attributed to the regrowth of invasive and resistant cells. Therefore, there is a pressing need to gain a deeper understanding of the mechanisms underlying GBM resistance to chemoradiation and its ability to infiltrate. Using a combination of transcriptomic, proteomic, and phosphoproteomic analyses, longitudinal imaging, organotypic cultures, functional assays, animal studies, and clinical data analyses, we demonstrate that chemoradiation and brain vasculature induce cell transition to a functional state named VC-Resist (vessel co-opting and resistant cell state). This cell state is midway along the transcriptomic axis between proneural and mesenchymal GBM cells and is closer to the AC/MES1-like state. VC-Resist GBM cells are highly vessel co-opting, allowing significant infiltration into the surrounding brain tissue and homing to the perivascular niche, which in turn induces even more VC-Resist transition. The molecular and functional characteristics of this FGFR1-YAP1-dependent GBM cell state, including resistance to DNA damage, enrichment in the G2M phase, and induction of senescence/stemness pathways, contribute to its enhanced resistance to chemoradiation. These findings demonstrate how vessel co-option, perivascular niche, and GBM cell plasticity jointly drive resistance to therapy during GBM recurrence. Show less

Neoplasms harboring a KAT6B/A::KANSL1 fusion were initially reported as benign (leiomyomas) and malignant (leiomyosarcomas, low-grade endometrial stromal sarcomas [LG-ESSs]) uterine neoplasms. However, they may represent an emerging entity characterized by clinical aggressiveness contrasting with a rather reassuring microscopic appearance. Here, we aimed to confirm that this neoplasm is a distinct clinicopathologic and molecular sarcoma and identify criteria that should alert pathologists and lead to KAT6B/A::KANSL1 fusion testing in routine practice. Therefore, we conducted a comprehensive clinical, histopathologic, immunohistochemical, and molecular study, including array comparative genomic hybridization, whole RNA-sequencing, unsupervised clustering, and cDNA mutational profile analyses of 16 tumors with KAT6B::KANSL1 fusion from 12 patients. At presentation, patients were peri-menopausal (median, 47.5 years), and the primary tumors were located in the uterine corpus (12/12, 100%), with an additional prevesical location in 1 (8.3%) of 12 cases. The relapse rate was 33.3% (3/9). All tumors (16/16, 100%) showed morphologic and immunohistochemical features overlapping between leiomyoma and endometrial stromal tumors. A whirling recurrent architecture (resembling fibromyxoid-ESS/fibrosarcoma) was found in 13 (81.3%) of 16 tumors. All tumors (16/16, 100%) exhibited numerous arterioliform vessels, and 13 (81.3%) of 18 had large hyalinized central vessels and collagen deposits. Estrogen and progesterone receptors were expressed in 16 (100%) of 16 and 14 (87.5%) of 16 tumors, respectively. Array comparative genomic hybridization performed on 10 tumors classified these neoplasms as simple genomic sarcomas. Whole RNA-sequencing on 16 samples and clustering analysis on primary tumors found that the KAT6B::KANSL1 fusion always occurred between exons 3 of KAT6B and 11 of KANSL1; no pathogenic variant was identified on cDNA, all neoplasms clustered together, close to LG-ESS, and pathway enrichment analysis showed cell proliferation and immune infiltrate recruitment pathway involvement. These results confirm that the sarcomas harboring a KAT6B/A::KANSL1 fusion represent a distinct clinicopathologic entity, close to LG-ESS but different, with clinical aggressiveness despite a reassuring morphology, for which the KAT6B/A::KANSL1 fusion is the molecular driver alteration. Show less

Garlic is a source of bioactive phytonutrients that may have anti-inflammatory or immunomodulatory properties. The mechanism(s) underlying the bioactivity of these compounds and their ability to regulate responses to enteric infections remains unclear. This study investigates if a garlic-derived preparation (PTSO-PTS) containing two organosulfur metabolites, propyl-propane thiosulfonate (PTSO), and propyl-propane thiosulfinate (PTS), regulate inflammatory responses in murine macrophages and intestinal epithelial cells (IEC) in vitro, as well as in a model of enteric parasite-induced inflammation. PTSO-PTS decreases lipopolysaccharide-induced secretion of TNFα, IL-6, and IL-27 in macrophages. RNA-sequencing demonstrates that PTSO-PTS strongly suppresses pathways related to immune and inflammatory signaling. PTSO-PTS induces the expression of a number of genes involved in antioxidant responses in IEC during exposure to antigens from the parasite Trichuris muris. In vivo, PTSO-PTS does not affect T. muris establishment or intestinal T-cell responses but significantly alters cecal transcriptomic responses. Notably, a reduction in T. muris-induced expression of Tnf, Saa2, and Nos2 is observed. Garlic-derived organosulfur compounds exert anti-inflammatory effects in macrophages and IEC, and regulate gene expression during intestinal infection. These compounds and related organic molecules may thus hold potential as functional food components to improve gut health in humans and animals. Show less

Effector functions of IgG Abs are regulated by their Fc N-glycosylation pattern. IgG Fc glycans that lack galactose and terminal sialic acid residues correlate with the severity of inflammatory (auto)immune disorders and have also been linked to protection against viral infection and discussed in the context of vaccine-induced protection. In contrast, sialylated IgG Abs have shown immunosuppressive effects. We sought to investigate IgG glycosylation programming during the germinal center (GC) reaction following immunization of mice with a foreign protein antigen and different adjuvants. Mice were analyzed for GC T-cell, B-cell, and plasma cell responses, as well as for antigen-specific serum IgG subclass titers and Fc glycosylation patterns. Different adjuvants induce distinct IgG This study's findings regarding adjuvant-dependent GC responses and IgG glycosylation programming may aid in the development of novel vaccination strategies to induce IgG Abs with both high affinity and defined Fc glycosylation patterns in the GC. Show less

The anti-obesity effects of two types of resistant starch (RS) in high-fat-diet-induced obese rats were investigated. The serum triglycerides, total cholesterol and malondialdehyde concentrations were significantly reduced, and the total antioxidant capacity, superoxide dismutase levels and glutathione peroxidase activity were increased by RS2 and RS4 consumption compared to the obesity group. A significant reduction in the serum glucose level and elevations in hepatic lipid metabolic enzyme activities were observed only for RS4 administration. Moreover, the expression levels of the fatty acid synthesis associated genes ACC and Fads1, the triglyceride synthesis and metabolism-related gene SREBP-1, the adipocyte differentiation gene PPARγ, the cholesterol synthesis associated gene HMGCR, and the gluconeogenesis associated gene GAPDH were all significantly down-regulated, whilst the lipid oxidation gene Acox1 and the liver function genes Gsta2, Nqo1, and Gclm were up-regulated in both administered groups. Additionally, RS4 performed well in up-regulating the expressions of Gsta2, Gsta3, Nqo1, and Egfr, and down-regulating LXRα, Igfbp1, and Pml. RS4 exhibited great advantages in reducing oxidative stress compared with RS2. Show less

The transient receptor potential melastatin type 6 (TRPM6) epithelial Mg(2+) channels participate in transcellular Mg(2+) transport in the kidney and intestine. Previous reports suggested a hormonal cAMP-dependent regulation of Mg(2+) reabsorption in the kidney. The molecular details of this process are, however, unknown. Adenylate cyclase 3 (Adcy3) has been shown to colocalize with the Na(+)/Cl(-) cotransporter, a marker of the distal convoluted segment of the kidney, the principal site of TRPM6 expression. Given the critical role of TRPM6 in Mg(2+) reabsorption, an inducible kidney-specific Adcy3 deletion mouse model was characterized for blood and urinary electrolyte disturbances under a normal--and low--Mg(2+) diet. Increased urinary Mg(2+) wasting and Trpm6 mRNA levels were observed in the urine and kidney of Adcy3-deleted animals compared with wild-type controls. Serum Mg(2+) concentration was significantly lower in Adcy3-deleted animals at day 7 on the low Mg(2+) diet. Using patch clamp electrophysiology, cell surface biotinylation, and total internal reflection fluorescence live cell imaging of transfected HEK293 cells, we demonstrated that cAMP signaling rapidly potentiates TRPM6 activity by promoting TRPM6 accumulation at the plasma membrane and increasing its single-channel conductance. Comparison of electrophysiological data from cells expressing the phosphorylation-deficient S1252A or phosphomimetic S1252D TRPM6 mutants suggests that phosphorylation at this intracellular residue participates in the observed stimulation of channel activity. Altogether, these data support a physiologically relevant magnesiotropic role of cAMP signaling in the kidney by a direct stimulatory action of protein kinase A on the plasma membrane trafficking and function of TRPM6 ion channels. Show less

Concerns remain regarding the heterogeneity in overlapping human immunodeficiency virus (HIV) risk behaviors among sex workers (SWs) in Pakistan; specifically, the degree to which SWs interact with people who inject drugs (PWID) through sex and/or needle sharing.Following an in-depth mapping performed in 2011 to determine the size and distribution of key populations at highest risk of HIV acquisition in Pakistan, a cross-sectional biological and behavioral survey was conducted among PWID, female (FSWs), male (MSWs), and hijra/transgender (HSWs) sex workers, and data from 8 major cities were used for analyses. Logistic regression was used to identify factors, including city of residence and mode of SW-client solicitation, contributing to the overlapping risks of drug injection and sexual interaction with PWID.The study comprised 8483 SWs (34.5% FSWs, 32.4% HSWs, and 33.1% MSWs). Among SWs who had sex with PWID, HSWs were 2.61 (95% confidence interval [CI], 1.19-5.74) and 1.99 (95% CI, 0.94-4.22) times more likely to inject drugs than MSWs and FSWs, respectively. There was up to a 3-fold difference in drug injecting probability, dependent on where and/or how the SW solicited clients. Compared with SWs in Larkana, the highest likelihood of drug injection use was among SWs in Multan (OR = 4.52; 95% CI: 3.27-6.26), followed by those in Lahore, Quetta, and Faisalabad.Heterogeneity exists in the overlapping patterns of HIV risk behaviors of SWs. The risk of drug injection among SWs also varies by city. Some means of sexual client solicitation may be along the pathway to overlapping HIV risk vulnerability due to increased likelihood of drug injection among SWs. There is a need to closely to monitor the mixing patterns between SWs and PWID and underlying structural factors, such as means of sexual client solicitation, that mediate HIV risk, and implement prevention programs customized to local subepidemics. Show less

The effect of resistant starch (RS) administration on biological parameters including blood glucose, lipids composition and oxidative stress of type 2 diabetic rats was investigated. The results showed blood glucose level, total cholesterol and triglycerides concentrations significantly reduced, and high-density lipoprotein cholesterol concentration was doubly increased in the rats of RS administration group compared to model control group (P<0.01). The analyses of genes involved in glucose and lipid metabolism pathways demonstrated that the expression levels of lipid oxidation gene Acox1, glycogen synthesis genes, GS2 and GYG1, and insulin-induced genes, Insig-1 and Insig-2, were significantly up-regulated (P<0.01). In contrast, fatty acids and triglycerides synthesis and metabolism-related gene SREBP-1, fatty acid synthesis gene Fads1 and gluconeogenesis gene G6PC1 were greatly down-regulated. The mechanism study shows that the lowering of blood glucose level in diabetic rats by feeding RS is regulated through promoting glycogen synthesis and inhibiting gluconeogenesis, and the increased lipid metabolism is modulated through promoting lipid oxidation and cholesterol homeostasis. Our study revealed for the first time that the regulation of hepatic genes expression involved in glucose and lipids metabolisms in diabetic rats could be achieved even at a moderate level of RS consumption. Show less

The fatty acid desaturase (Fads) cluster is composed of three genes encoding for the Δ5- and Δ6-desaturases and FADS3. The two former proteins are involved in the fatty acid biosynthesis; the latter one shares a high sequence identity but has still no attributed function. In a previous work performed in rat, we described three isoforms of FADS3 expressed in a tissue-dependent manner. In the present study, we demonstrated a specific subcellular targeting depending on the isoform. In cultured hepatocytes, which mainly expressed the 51 kDa protein, FADS3 was unexpectedly present in the cytosolic fraction, but was also secreted in the extracellular matrix on fibronectin-containing fibers. The secretion pathway was investigated and we determined the presence of exosome-like vesicles on the FADS3-stained fibers. In parallel, FADS3 was detected in blood of hepatic vessel, and particularly in serum. In conclusion, this study demonstrated a very specific intra- and extracellular location of FADS3 in comparison with the Δ5- and Δ6-desaturases, suggesting a unique function for this putative desaturase, even if no activity has been yet identified neither in the extracellular matrix of hepatocytes nor in serum. Show less

Fatty acid desaturases play critical roles in regulating the biosynthesis of unsaturated fatty acids in all biological kingdoms. As opposed to plants, mammals are so far characterized by the absence of desaturases introducing additional double bonds at the methyl-end site of fatty acids. However, the function of the mammalian fatty acid desaturase 3 (FADS3) gene remains unknown. This gene is located within the FADS cluster and presents a high nucleotide sequence homology with FADS1 (Δ5-desaturase) and FADS2 (Δ6-desaturase). Here, we show that rat FADS3 displays no common Δ5-, Δ6- or Δ9-desaturase activity but is able to catalyze the unexpected Δ13-desaturation of trans-vaccenate. Although there is no standard for complete conclusive identification, structural characterization strongly suggests that the Δ11,13-conjugated linoleic acid (CLA) produced by FADS3 from trans-vaccenate is the trans11,cis13-CLA isomer. In rat hepatocytes, knockdown of FADS3 expression specifically reduces trans-vaccenate Δ13-desaturation. Evidence is presented that FADS3 is the first "methyl-end" fatty acid desaturase functionally characterized in mammals. Show less

Since its identification in 2000, no function has been attributed to the Fatty Acid Desaturase 3 (Fads3) gene. This gene is located within the Fads cluster, which also contains Fads1 and Fads2, coding respectively for the Δ5- and Δ6- desaturases. Based on the sequence homology between these three genes, Fads3 may be a new fatty acid desaturase. It is thus essential to understand its involvement in Polyunsaturated Fatty Acid (PUFA) biosynthesis in order to improve our knowledge on lipid metabolism. Gene expression studies provided evidences on the specificity of Fads3 compared to Fads1 and Fads2, concerning the tissue distribution, alternative splicing and regulation. These works also identified possible physiological functions in which Fads3 could be involved. Thus, the Fads3 gene was transcripted in many tissues, and displayed a weak expression in the liver compared to other organs such as the lung or spleen. Fads3 was also showed to be a target gene for NK-κB, MYCN or p63 transcription factors and could consequently be involved in cell survival mechanisms. Polymorphism analysis underlined the possible implication of Fads3 in lipid homeostasis, particularly by modulating cholesterol and triglyceride plasma levels. In terms of proteins, FADS3 has been recently described in rodents. One of the identified isoforms may display the classical structure of a fatty acid desaturase but no enzymatic activity has been observed yet. Therefore, it is essential to consider the desaturase diversity in terms of catalysis and substrates to elucidate the FADS3 function. Show less

In 2000, Marquardt et al. (A. Marquardt, H. Stöhr, K. White, and B. H. F. Weber. 2000. cDNA cloning, genomic structure, and chromosomal localization of three members of the human fatty acid desaturase family. Genomics. 66: 176-183.) described the genomic structure of the fatty acid desaturase (FADS) cluster in humans. This cluster includes the FADS1 and FADS2 genes encoding, respectively, for the Delta 5- and Delta 6-desaturases involved in polyunsaturated fatty acid biosynthesis. A third gene, named FADS3, has recently been identified but no functional role has yet been attributed to the putative FADS3 protein. In this study, we investigated the FADS3 occurrence in rat tissues by using two specific polyclonal antibodies directed against the N-terminal and C-terminal ends of rat FADS3. Our results showed three potential protein isoforms of FADS3 (75 kDa, 51 kDa, and 37 kDa) present in a tissue-dependent manner. The occurrence of these FADS3 isoforms did not depend on the mRNA level determined by real-time PCR. In parallel, mouse tissues were also tested and showed the same three FADS3 isoforms but with a different tissue distribution. Finally, we reported the existence of FADS3 in human cells and tissues but different new isoforms were identified. To conclude, we showed in this study that FADS3 does exist under multiple protein isoforms depending on the mammalian tissues. These results will help further investigations to determine the physiological function of FADS3. Show less

Mutations that inactivate LET-767 are shown to affect growth, reproduction, and development in Caenorhabditis elegans. Sequence analysis indicates that LET-767 shares the highest homology with human types 3 and 12 17beta-hydroxysteroid dehydrogenases (17beta-HSD3 and 12). Using LET-767 transiently transfected into human embryonic kidney-293 cells, we have found that the enzyme catalyzes the transformation of both 4-androstenedione into testosterone and estrone into estradiol, similar to that of mouse 17beta-HSD12 but different from human and primate enzymes that catalyze the transformation of estrone into estradiol. Previously, we have shown that amino acid F234 in human 17beta-HSD12 is responsible for the selectivity of the enzyme toward estrogens. To assess whether this amino acid position 234 in LET-767 could play a role in androgen-estrogen selectivity, we have changed the methionine M234 in LET-767 into F. The results show that the M234F change causes the loss of the ability to transform androstenedione into testosterone, while conserving the ability to transform estrone into estradiol, thus confirming the role of amino acid position 234 in substrate selectivity. To further analyze the structure-function relationship of this enzyme, we have changed the three amino acids corresponding to lethal mutations in let-767 gene. The data show that these mutations strongly affect the ability of LET-767 to convert estrone in to estradiol and abolish its ability to transform androstenedione into testosterone. The high conservation of the active site and amino acids responsible for enzymatic activity and substrate selectivity strongly suggests that LET-767 shares a common ancestor with human 17beta-HSD3 and 12. Show less