Reduction in BDNF from inefficient precursor conversion influences nest building and promotes depressive-like behavior in mice

Kojima, M.; Otabi, H.; Kumanogoh, H.; Toyoda, A.; Ikawa, M.; Okabe, M.; Mizui, T. Reduction in BDNF from Inefficient Precursor Conversion Influences Nest Building and Promotes Depressive-Like Behavior in Mice. Int. J. Mol. Sci. 2020, 21, 3984. https://doi.org/10.3390/ijms2111398

Reduction in BDNF from Inefficient Precursor Conversion Influences Nest Building and Promotes Depressive-Like Behavior in Mice

We generated a knock-in mouse line in which the gene encoding brain-derived neurotrophic factor (Bdnf) was replaced with a sequence for proBDNF containing human single nucleotide polymorphisms encoding arginines proximal to the cleavage site (R125M and R127L). The ratio of the mature form of BDNF (mBDNF) to precursor BDNF (proBDNF) in hippocampal tissue lysates was decreased in a manner dependent on the number of copies of the mutant gene, indicating that the mutations inhibited proteolytic conversion of proBDNF into mBDNF. Although homozygous mice had a proBDNF/mBDNF ratio of ~9:1, they survived until adulthood. The levels of mBDNF were reduced by 57% in heterozygous mutant mice, which exhibited a depressive-like behavior in the tail suspension test and weight gain when housed in social isolation, showing that impaired proBDNF cleavage contributes to stress-induced depressive-like phenotypes. Furthermore, socially isolated heterozygous mice displayed a pronounced deficit in daily nest-building behaviors. These findings suggest that the decreased production of mBDNF by impaired proBDNF cleavage disturbs daily activities in mice

Effects of Partially Hydrolyzed Guar Gum Supplementation on the Fecal Microbiotas of Piglets

Probiotics and prebiotics have become viable alternatives of growth-promoting antimicrobials in animal production. Here, we tested partially hydrolyzed guar gum (PHGG) as a possible prebiotic for piglets in the commercial farm. Five hundred and ninety-four piglets were used for the experiments, with 293 given a normal pig feed (control), while the rest the feed plus 0.06% (w/w) of PHGG (PHGG). One and three months post-PHGG supplementation, fecal samples were collected from randomly selected 20 piglets in each group and analyzed for microbiota and organic acid concentrations. Notably, the abundance of Streptococcus, and unclassified Ruminococcaceae were lower (p < 0.05) in PHGG than in control, one-month post-supplementation. Lactobacillus and Prevotella were higher (p < 0.05), while Streptococcus was lower (p < 0.05), in PHGG than in control, three months post-supplementation. The concentrations of acetate, propionate, and butyrate were greater in PHGG than in control, three months post-supplementation. Finally, PHGG grew faster and had fewer deaths until slaughter time (p < 0.05), than control. We concluded that PHGG not only was an effective prebiotic to alter gut microbiota of weanling piglets but also can possibly promote body weight accretion and health