Project description:This study examines the role of early exposure to gut microbes and poor diet on microglial function in mice. Groups = control (CON), malnourished (MAL), and malnourished + microbial exposure (E/MALBG). CD11b+ cells (microglial enrichment) were isolated from whole mouse brains (Adult Brain Disruption Kit, Miltenyi Biotec). After sample quality control (Agilent 2100 Bioanalyzer), qualifying samples were sent for RNA-Seq (Illumina NextSeq 500 with Paired End 42bp × 42bp reads; demultiplexed: Illumina's bcl2fastq2). Following alignment against mouse reference genes (STAR aligner), DEG analyses was conducted using the DESeq2 pipeline.
Project description:Severe malnutrition in young children is associated with signs of hepatic dysfunction such as steatosis and hypoalbuminemia, but its etiology is unknown. To investigate the underlying mechanisms of hepatic dysfunction we used a rat model of malnutrition by placing weanling rats on a low protein or control diet (5% or 20% of calories from protein, respectively) for four weeks. Low protein diet-fed rats developed hypoalbuminemia and severe hepatic steatosis, consistent with the human phenotype. Hepatic peroxisome content was decreased and metabolomic analysis indicated impaired peroxisomal function. Loss of peroxisomes was followed by accumulation of dysfunctional mitochondria and decreased hepatic ATP levels. Fenofibrate supplementation restored hepatic peroxisome abundance and increased mitochondrial fatty acid β-oxidation capacity, resulting in reduced steatosis and normalization of ATP and plasma albumin levels. These findings provide important insight into the metabolic disturbances associated with malnutrition and have potentially profound clinical consequences with respect to the management of malnourished children worldwide.
Project description:We illustrate an approach for integrating preclinical gnotobiotic animal models with human studies to understand the contributions of perturbed gut microbiota development to childhood undernutrition, and to identify new microbiota-directed therapeutic concepts/leads. Combining metabolomic and proteomic analyses of serially collected plasma samples with metagenomic analyses of serially collected fecal samples, we characterized the biological state of Bangladeshi children with severe acute malnutrition (SAM) as they transitioned to moderate acute malnutrition (MAM) after standard treatment. Gnotobiotic mice were subsequently colonized with a defined consortium of bacterial strains representing different stages of microbiota development in healthy children from Bangladesh. Administering different combinations of Bangladeshi complementary food ingredients to colonized mice and germ-free controls revealed diet-dependent changes in representation and metabolism of targeted weaning-phase strains, including accompanying increases in branched-chain amino acids, plus diet- and colonization-dependent augmentation of IGF-1/mTOR signaling. Host and microbial effects of microbiota-directed complementary food (MDCF) prototypes were subsequently examined in gnotobiotic mice colonized with post-SAM MAM microbiota and in gnotobiotic piglets colonized with a defined consortium of targeted age- and growth-discriminatory bacteria. Finally, ar andomized, double-blind study revealed a lead MDCF that affected the representation of targeted bacterial taxa and increased levels of biomarkers and mediators of growth, bone formation, neurodevelopment, and immune function.
Project description:Effects of current therapeutic foods in undernourished Bangladeshi children compared to microbiota-directed food prototypes in gnotobiotic mice and piglets
Project description:Whole blood gene expression profiling from well and malnourished Indian individuals with TB and severely malnourished household contacts with latent TB infection (LTBI). Severe malnutrition was defined as body mass index (BMI) <16. kg/m2 in adults and based on weight-for-height Z scores in children <18 years. Gene expression was measured using RNA-sequencing.
