Identification and Characterization of a Novel Species of Genus Akkermansia with Metabolic Health Effects in a Diet-Induced Obesity Mouse Model

Abstract

Akkermansia muciniphila is a well-known bacterium with the ability to degrade mucin. This metabolic capability is believed to play an important role in the colonization of this bacterium in the gut. In this study, we report the identification and characterization of a novel Akkermansia sp. DSM 33459 isolated from human feces of a healthy donor. Phylogenetic analysis based on the genome-wide average nucleotide identity indicated that the Akkermansia sp. DSM 33459 has only 87.5% similarity with the type strain A. muciniphila ATCC BAA-835. Akkermansia sp. DSM 33459 showed significant differences in its fatty acid profile and carbon utilization as compared to the type strain. The Akkermansia sp. DSM 33459 strain was tested in a preclinical obesity model to determine its effect on metabolic markers. Akkermansia sp. DSM 33459 showed significant improvement in body weight, total fat weight, and resistin and insulin levels. Interestingly, these effects were more pronounced with the live form as compared to a pasteurized form of the strain. The strain showed production of agmatine, suggesting a potential novel mechanism for supporting metabolic and cognitive health. Based on its phenotypic features and phylogenetic position, it is proposed that this isolate represents a novel species in the genus Akkermansia and a promising therapeutic candidate for the management of metabolic diseases.

Keywords: Akkermansia sp.; metabolic health; microbiome.

Figure 1

A phylogenetic tree consisting of Akkermansia sp. DSM 33459. The tree was reconstructed with the neighbor-joining method with 1000 bootstraps. Numbers represent bootstrap values. The legend bar indicates 5% sequence divergence. Chlamydia trachomatis was used as an outgroup.

Figure 2

Determination of preferred carbon source for growth.

Figure 3

Sample comparison of CE-TOFMS relative peak areas of Agmatine. Akkermansia sp. DSM 33459 and A. muciniphila BAA-835 supernatants were collected after 24 h of growth and analyzed by CE-TOF-MS.

Figure 4

MetaCyc pathway for bacterial conversion of arginine to agmatine (ID: PWY0−1299) [43].

Figure 5

ATP amounts were detected in the supernatants for A. muciniphila ATCC BAA-835 at time 0 (A) and after 8 h of growth (B). ATP was estimated in the supernatants from Akkermansia sp. DSM 33459 at time 0 (C) and after 8 h of growth (D). Each experiment was conducted with duplicate wells and was repeated at least three times. Data are presented as mean ± SEM. One-way, two tailed ANOVA followed by Dunnett’s multiple comparisons test were used for statistical analysis. **, p < 0.01; ***, p < 0.001, compared to Media + ATP.

Figure 6

Akkermansia sp. DSM33449 negates weight increase and reduces fat accumulation in a DIO mouse model (n = 10). (A) Growth curve of animals fed a standard chow (Chow) or high-fat diet (HFD) and treated by oral gavage with a solution of vehicle (PBS + Glycerol) or Akkermansia sp. DSM 33459 frozen (Akk^Gly) or pasteurized (Akk^Pas) or lyophilized (Akk^Lyo) for 12 weeks. (B) Difference in fat accumulation over the 12-week treatment period. (C) Difference in liver weight over the 12-week treatment period. Data are presented as mean ± SEM. *, p < 0.05; **, p < 0.01; ****, p < 0.0001, compared to vehicle.

Figure 7

Akkermansia sp. DSM33449 modulates resistin levels in a DIO mouse model (n = 10). Serum resistin levels of animals fed on a standard chow (chow) or high-fat diet (HFD) and treated by oral gavage with a solution of vehicle (PBS + Glycerol) or Akkermansia sp. DSM 33459 frozen (Akk^Gly) or pasteurized (Akk^Pas) or lyophilized (Akk^Lyo) for 12 weeks. Data are presented as mean ± SEM. *, p < 0.05; **, p < 0.01; ***, p < 0.001, compared to vehicle.

Figure 8

Akkermansia sp. DSM33449 modulates the insulin levels in a DIO mouse model (n = 10). (A) Serum insulin levels of animals fed on a standard chow (Chow) or high-fat diet (HFD) and treated by oral gavage with a solution of vehicle (PBS + Glycerol) or Akkermansia sp. DSM 33459 frozen (Akk^Gly) or pasteurized (Akk^Pas) or lyophilized (Akk^Lyo) for 12 weeks. (B) AUC for serum insulin levels. Data are presented as mean ± SEM. *, p < 0.05; ***, p < 0.001, compared to vehicle.

Figure 9

Akkermansia sp. DSM33459 improves HOMA-IR in a DIO mouse model (n = 10). Serum insulin and glucose levels were measured and used for the determination of HOMA-IR. HOMA-IR of animals fed on a standard chow (Chow) or high-fat diet (HFD) and treated by oral gavage with a solution of vehicle (PBS + Glycerol) or Akkermansia sp. DSM 33459 frozen (Akk^Gly) or pasteurized (Akk^Pas) or lyophilized (Akk^Lyo) for 12 weeks. Data are presented as mean ± SEM. *, p < 0.05; ***, p < 0.001, compared to vehicle.

Figure 10

Engraftment of Akkermansia sp. DSM 33459 in the mice GI tract. Relative abundance of A. muciniphila and Akkermansia sp. DSM 33459 in mice fecal samples at different time points.

Figure 11

Similar modulation of peroxisomal proteins by Akkermansia sp. DSM 33459 and drug control group.