Publications by authors named "Jean Buteau"

The emergence of carbapenem-resistant (CRKP) poses a significant public health threat, particularly in low- and middle-income countries (LMICs) with limited surveillance and treatment options. This study examines the genetic diversity, resistance patterns, and transmission dynamics of 66 CRKP isolates recovered over 5 years (2015-2019) after the first case of CRKP was identified at a tertiary care hospital in Lima, Peru. Our findings reveal a shift from to as the dominant carbapenemase gene after 2017.

View Article and Find Full Text PDF

Cytidine triphosphate:phosphocholine cytidylyltransferase-α (CTα) is the rate limiting enzyme in the major pathway for de novo phosphatidylcholine (PC) synthesis. When CTα is deleted specifically in intestinal epithelial cells of adult mice (CTα mice) fed a high-fat diet they present with weight loss, lipid malabsorption, and high postprandial GLP-1 levels. The current study aimed to characterize the changes that occur in the small intestines of CTα mice using transcriptomics and to determine whether intestinal function could be rescued in CTα mice.

View Article and Find Full Text PDF

SUMOylation reduces oxidative stress and preserves islet mass at the expense of robust insulin secretion. To investigate a role for the deSUMOylating enzyme sentrin-specific protease 1 (SENP1) following metabolic stress, we put pancreas/gut-specific SENP1 knockout (pSENP1-KO) mice on a high-fat diet (HFD). Male pSENP1-KO mice were more glucose intolerant following HFD than littermate controls but only in response to oral glucose.

View Article and Find Full Text PDF

Objective: Frasier syndrome is a rare genetic nephropathy characterized by the presence of progressive glomerulopathy with proteinuria associated with male pseudo hermaphroditism. This case study described a picture of a young boy where the clinical suspicion context reminded the Frasier syndrome. To our knowledge, this case is the first described in Haiti.

View Article and Find Full Text PDF

Neonatal antibiotics administered to human infants initiate gut microbiota dysbiosis that may have long-term effects on body weight and metabolism. We examined antibiotic-induced adaptations in pancreatic islets of the piglet, a well-accepted model of human infant microbiota and pancreas development. Neonatal piglets randomized to amoxicillin [30 mg/kg body wt/day; = 7, antibiotic (ANTI)] or placebo [vehicle control; = 7, control (CON)] from ()- were euthanized at , , and .

View Article and Find Full Text PDF

Background & Aims: Patients with ulcerative colitis have low concentrations of the major membrane lipid phosphatidylcholine (PC) in gastrointestinal mucus, suggesting that defects in colonic PC metabolism might be involved in the development of colitis. To determine the precise role that PC plays in colonic barrier function, we examined mice with intestinal epithelial cell (IEC)-specific deletion of the rate-limiting enzyme in the major pathway for PC synthesis: cytidine triphosphate:phosphocholine cytidylyltransferase-α (CTα mice).

Methods: Colonic tissue of CTα mice and control mice was analyzed by histology, immunofluorescence, electron microscopy, quantitative polymerase chain reaction, Western blot, and thin-layer chromatography.

View Article and Find Full Text PDF

Nor1, the third member of the Nr4a subfamily of nuclear receptor, is garnering increased interest in view of its role in the regulation of glucose homeostasis. Our previous study highlighted a proapoptotic role of Nor1 in pancreatic beta cells and showed that Nor1 expression was increased in islets isolated from type 2 diabetic individuals, suggesting that Nor1 could mediate the deterioration of islet function in type 2 diabetes. However, the mechanism remains incompletely understood.

View Article and Find Full Text PDF

The Nr4a subfamily of nuclear receptor comprises three members in mammalian cells: Nur77/Nr4a1, Nurr1/Nr4a2, and Nor1/Nr4a3. Nr4a proteins play key roles in the regulation of glucose homeostasis in peripheral metabolic tissues. However, their biological functions in β-cells remain relatively uncharacterized.

View Article and Find Full Text PDF

Objective: Interpersonal violence affecting women and children is increasingly recognized as a public health priority in humanitarian emergencies. Yet, research and intervention efforts have been fragmented across gender-based violence and child protection sectors. Using data from the Transforming Households: Reducing Incidence of Violence in Emergencies (THRIVE) project, this study sought to qualitatively investigate the intersecting drivers of multiple forms of violence in Côteaux, Haiti, while obtaining insight on how these drivers may be influenced by a humanitarian emergency.

View Article and Find Full Text PDF

Hyperinsulinemic hypoglycemia syndrome (HIHG) is a rare complication of roux-en-Y gastric bypass surgery. The pathology is associated with an excessive function of pancreatic beta-cells, and requires pancreas resection in patients that are recalcitrant to nutritional and pharmacological interventions. The exact prevalence is not clearly understood and the underlying mechanisms not yet fully characterized.

View Article and Find Full Text PDF

De novo phosphatidylcholine (PC) synthesis via CTP:phosphocholine cytidylyltransferase-α (CTα) is required for VLDL secretion. To determine the precise role of de novo PC synthesis in intestinal lipid metabolism, we deleted CTα exclusively in the intestinal epithelium of mice (CTα mice). When fed a chow diet, CTα mice showed normal fat absorption despite a ∼30% decrease in intestinal PC concentrations relative to control mice, suggesting that biliary PC can fully support chylomicron secretion under these conditions.

View Article and Find Full Text PDF

Aims/hypothesis: Heat shock factor protein 1 (HSF1) is a transcription factor that regulates the expression of key molecular chaperones, thereby orchestrating the cellular response to stress. This system was recently implicated in the control of insulin sensitivity and is therefore being scrutinised as a novel therapeutic avenue for type 2 diabetes. However, the regulation and biological actions of HSF1 in beta cells remain elusive.

View Article and Find Full Text PDF

Establishing a programme for the prevention and treatment of acute kidney injury, chronic kidney disease and end-stage renal disease in a developing country involves unique challenges. We became involved in a collaborative effort to improve nephrology care in Haiti after participating in the emergency response to the 2010 earthquake. The focus of this ongoing project is overcoming barriers to implementation with the goal of improving training and resources for Haitian health-care workers and developing programmes for renal disease prevention and treatment in a setting of limited resources.

View Article and Find Full Text PDF

The leucine-to-glutamate (Leu→Glu) pathway, which metabolizes the carbon atoms of l-leucine to form l-glutamate, was studied by incubation of rat tissue segments with l-[U-(14)C]leucine and estimation of the [(14)C]glutamate formed. Metabolism of the leucine carbon chain occurs in most rat tissues, but maximal activity of the Leu→Glu pathway for glutamate formation is limited to the thoracic aorta and pancreas. In rat aorta, the Leu→Glu pathway functions to relax the underlying smooth muscle; its functions in the pancreas are unknown.

View Article and Find Full Text PDF

The tumor suppressor gene ST18 was originally characterized as the third member of the neural zinc finger transcription factor family. However, little is known about its biological functions. Herein, we demonstrate that, in the pancreas, ST18 expression is restricted to endocrine cells.

View Article and Find Full Text PDF

Type 2 diabetes is characterized by both insulin resistance and progressive deterioration of β-cell function. The forkhead transcription factor FoxO1 is a prominent mediator of insulin signaling in β-cells. We reasoned that identification of FoxO1 target genes in β-cells could reveal mechanisms linking β-cell dysfunction to insulin resistance.

View Article and Find Full Text PDF

Glucagon-like peptide-1 (GLP-1), a glucoincretin hormone secreted by intestinal L cells, is a potent growth factor for the pancreatic β-cell. The development of GLP-1 mimetics and enhancers as a novel class of anti-diabetes medications underpins the importance of elucidating the molecular basis of GLP-1 signaling. In the present study, we sought to test the hypothesis that β-arrestin-mediated recruitment of c-Src underlies the proliferative action of GLP-1 in β-cells.

View Article and Find Full Text PDF

Objective: The glucoincretin hormone glucagon-like peptide 1 (GLP-1) enhances glucose-stimulated insulin secretion and stimulates pancreatic β-cell mass expansion. We have previously shown that the forkhead transcription factor FoxO1 is a prominent transcriptional effector of GLP-1 signaling in the β-cell. FoxO1 activity is subject to a complex regulation by Akt-dependent phosphorylation and SirT1-mediated deacetylation.

View Article and Find Full Text PDF

Elevated glucose and saturated fatty acids synergize in inducing apoptosis in INS832/13 cells and in human islet cells. In order to gain insight into the molecular mechanism(s) of glucolipotoxicity (Gltox), gene profiling and metabolic analyses were performed in INS832/13 cells cultured at 5 or 20 mm glucose in the absence or presence of palmitate. Expression changes were observed for transcripts involved in mitochondrial, lipid, and glucose metabolism.

View Article and Find Full Text PDF

Glucagon-like peptide-1 (GLP-1) is a glucoincretin hormone most intensively studied for its actions on insulin secreting beta-cells. GLP-1 and its receptor are also found in brain and accumulating evidence indicates that GLP-1 has neuroprotective actions. Here, we investigated whether GLP-1 protects neuronal cells from death evoked by nerve growth factor (NGF) withdrawal.

View Article and Find Full Text PDF

Gain-of-function mutations in NOTCH1 are common in T-cell lymphoblastic leukemias and lymphomas (T-ALL), making this receptor a promising target for drugs such as gamma-secretase inhibitors, which block a proteolytic cleavage required for NOTCH1 activation. However, the enthusiasm for these therapies has been tempered by tumor resistance and the paucity of information on the oncogenic programs regulated by oncogenic NOTCH1. Here we show that NOTCH1 regulates the expression of PTEN (encoding phosphatase and tensin homolog) and the activity of the phosphoinositol-3 kinase (PI3K)-AKT signaling pathway in normal and leukemic T cells.

View Article and Find Full Text PDF

Diabetes is associated with decreased pancreatic beta-cell function and mass. It is unclear whether diabetes treatment should aim at restoring beta-cell performance/mass or at inducing "beta-cell rest" to prevent further deterioration. The transcription factor Foxo1 protects beta-cells against oxidative stress induced by hyperglycemia and prevents beta-cell replication in insulin-resistant states.

View Article and Find Full Text PDF

The glucoincretin hormone glucagon-like peptide-1 (GLP-1) increases pancreatic beta-cell proliferation and survival through sequential activation of the epidermal growth factor receptor (EGFR), phosphatidylinositol-3 kinase (PI 3-kinase), and Akt. We investigated the role of transcription factor FoxO1 in the proliferative and antiapoptotic actions of GLP-1 in beta-cells. GLP-1 inhibited FoxO1 through phosphorylation-dependent nuclear exclusion in pancreatic beta (INS832/13) cells.

View Article and Find Full Text PDF

Activating transcription factor 3 (ATF3) is a stress-inducible gene and encodes a member of the ATF/CREB family of transcription factors. However, the physiological significance of ATF3 induction by stress signals is not clear. In this report, we describe several lines of evidence supporting a role of ATF3 in stress-induced beta-cell apoptosis.

View Article and Find Full Text PDF