A. Muciniphila; a Microbiome Mediator of Tetrahydrocannabinol Induced Weight Loss?

Abstract

Intro The gut microbiome is increasingly known to play a role in obesity; a major health concern globally. It has been noted that cannabis users tend to have lower body mass indexes than non-users, and theorized that the delta(9)-tetrahydrocannabinol (THC) in cannabis could play a role in this effect. We hypothesized that the gut microbiome may play a key role in THC induced weight loss. Methods We investigated temporal effects of oral THC supplementation on the microbiome of male and female mice made obese by the D12311 diet from Research. At day 0, the THC group (male = 10, female = 8) was supplemented with 10mg/kg of oral THC. Control (male = 6, female = 3) was supplemented with the sweetened milk vehicle. Fecal samples were collected at days 0, 2, 9, and 15, prepared for V4 16s sequencing, and analyzed with QIIME2 and R. Beta diversity by weighted UniFrac PERMANOVA. Multilevel modeling (MLM) was performed at sequentially deeper taxa to identify significant effects of THC treatment on microbiome abundance. We evaluated microbiomes of both sexes for conserved effects. Results Over the 15-day experiment, male and female mice treated with THC demonstrated weight loss of 12.5±4.1% and 15.7±5.8% respectively, compared with 0.4±1.4% and 1.3±4.6% among controls. THC treatment had a significant effect on microbiome beta diversity in both males (PERMANOVA, F=5.32, P=0.001) and females (PERMANOVA, F=4.22, P=0.011). THC treatment increased Shannon alpha diversity from baseline in females (T-test, p <0.01). MLM identified several taxa which were significantly up-regulated between days 0 and 2 (T2 spikes). Here we present effects which were conserved between sexes. T2 spikes in THC treated mice were significant at a phyla level among Proteobacteria, Verrucomicrobia, Bacteroidetes, and Firmicutes. The Verrucomicrobia spike represented a single species, Akkermansia muciniphila, in both males and females which increased 9.8±6% and 7.9±9.6% respectively. Relative frequency of the A. muciniphila T2 spike was significantly negatively correlated with weight loss (GLS, est = -0.66, SE = 0.18, p<0.01). This effect was conserved between sexes. Few other significant effects on the microbiome were conserved between genders. Among Firmicutes, S. variabile showed a large T2 spike in males but not females and a significant longitudinal upregulation in females but not males, and Ruminococcus showed a significant upregulation in males. Discussion T2 A. muciniphila spikes occurred in THC treated mice only and occurred before THC-induced weight loss was achieved. This suggests a possible mechanistic role of A. muciniphila. A. muciniphila has been identified by other studies as a potential therapeutic target for obesity, diabetes, and metabolic syndrome. Ruminococcaceae have been implicated in butyrate production, which is known to increase mitochondrial activity, improve insulin sensitivity, and protect against diet induced obesity. These findings support that the gut microbiome may have an integral role in THC induced weight loss, potentially via A. muciniphila up-regulation.