Journal: Bone Research

Article Title: Akkermansia muciniphila attenuates intervertebral disc degeneration via extracellular vesicle-mediated delivery of the effector protein B2UKX5

doi: 10.1038/s41413-026-00541-5

Figure Lengend Snippet: Supplementation of Akk and Akk -EVs attenuates IVDD in multiple in vivo models. a Representative ex vivo fluorescence images of L2-6 lumbar intervertebral discs 24 h after intravenous injection of DiR-labeled Akk -EVs in mice. Scale bar: 3 mm. b Quantitative analysis of mean fluorescence intensity across L2-6 in intervertebral discs. n = 3 per group. c Schematic of the experimental protocol for Akk and Akk -EVs treatment in needle puncture mice. d Representative T2-weighted MRI images of the C8-9 caudal spine. Scale bar: 1 mm. e Statistical analysis of Pfirrmann grading for the C8-9 caudal segment. n = 8 per group. Representative DR images ( f ) and micro-CT 3D reconstruction images ( g ) of the caudal spine. Scale bar: 1 mm. h DHI after 12 weeks of needle puncture at the C8-9 caudal segment. n = 8 per group. Representative H&E ( i ) and SO/FG ( j ) stained images showing the macroscopic morphology of the disc, NP, and AF in the C8-9 segment. Scale bars: 200 μm (Disc) or 50 μm (NP, AF). k Histological scores for the C8-9 segment. n = 8 per group. l Schematic of the experimental protocol for Akk and Akk -EVs treatment in naturally aging mice. m Representative T2-weighted MRI images of the lumbar spine in mice. Scale bar: 1 mm. n Statistical analysis of the average Pfirrmann grade in the L1-S1 lumbar disc segments. n = 9–14 per group. o Representative micro-CT 3D reconstruction images of the L5-6 lumbar disc segments. Scale bar: 1 mm. p Statistical analysis of the mean DHI in the L2-6 lumbar disc segments. n = 8–10 per group. q , r Representative images of H&E (q) and SO/FG (r) staining showing the macroscopic morphology of intervertebral disc (Disc), nucleus pulposus (NP), annulus fibrosus (AF), and endplate (EP) in the L5-6 lumbar disc segment. Scale bars: 200 μm (Disc) or 50 μm (NP, AF, EP). s Statistical analysis of histological scores for each lumbar segment (L2-6). n = 8–10 per group. t Representative IF images showing the expression of COL2, ACAN, and MMP13 in the L5-6 lumbar intervertebral discs. Scale bar: 200 μm. u Quantitative analysis of COL2, ACAN, and MMP13 expression. n = 8–10 per group. Data are presented as mean ± SD. Statistical significance was determined by unpaired Student’s t -test ( b ) or one-way ANOVA followed by Bonferroni post hoc test ( e , h , k , n , p , s , u )

Article Snippet: Sections were blocked with 10% goat serum before incubation with primary antibodies: COL2 (1:300; GB11021-100, Servicebio), ACAN (1:300; GB11373-100, Servicebio), MMP13 (1:300; GB11247-100, Servicebio), p16 Ink4a (1:200; GB111143-100, Servicebio), IL-6 (1:300; GB11117-100, Servicebio), Akk -EVs-specific antibody (1:50, custom-made, produced by Wuhan FriendBio Technology Co) and B2UKX5-specific antibody (1:50, custom-made, produced by Nanjing GenScript Biotechnology Co).

Techniques: In Vivo, Ex Vivo, Fluorescence, Injection, Labeling, Micro-CT, Staining, Expressing

Journal: Bone Research

Article Title: Akkermansia muciniphila attenuates intervertebral disc degeneration via extracellular vesicle-mediated delivery of the effector protein B2UKX5

doi: 10.1038/s41413-026-00541-5

Figure Lengend Snippet: B2UKX5 as a potential functional protein in Akk -EVs against IVDD. Hierarchical clustering heatmap ( a ) and count ( b ) of differentially enriched proteins between Akk and Akk -EVs. c Functional annotation for the highly enriched 388 proteins using the COG database. d Relative enrichment levels of the five selected candidate proteins in Akk -EVs compared to Akk , displayed as Akk -EVs/ Akk ratios. e Heatmap showing qPCR-based expression levels of MMP13 , ADAMTS5 , TNF , and CDKN1A in TNF-α-treated human NP cells following treatment with the five candidate proteins. n = 3 per group. f Cytotoxicity assessment of B2UKX5 in human NP cells using Cell Counting Kit-8 assay after 24 h treatment under indicated concentrations. Cell viability is expressed relative to vehicle control. n = 3 per group. g Representative IF staining of COL2 (green) in TNF-α-treated NP cells after B2UKX5 intervention; Nuclei are counterstained with DAPI (blue). Scale bar: 100 μm. h Quantification of COL2 mean fluorescence intensity in human NP cells. n = 3 per group. i Representative IF staining of MMP13 (green) in TNF-α-treated NP cells after B2UKX5 intervention; Nuclei are counterstained with DAPI (blue). Scale bar: 100 μm. j Quantification of MMP13 mean fluorescence intensity in human NP cells. n = 3 per group. k Correlation analysis between age, IVDD grading (Pfirrmann), and serum B2UKX5 levels in human subjects. n = 79. l Quantification of B2UKX5 levels in serum from mice of different age groups. n = 15–16 per group. m Representative IF staining of B2UKX5 (green) in human NP tissue from patients with varying degrees of IVDD; Nuclei are counterstained with DAPI (blue). Scale bar: 50 μm. n Quantification of B2UKX5-positive area (%) in human NP tissue; n = 9–11 per group. o Representative IF staining of B2UKX5 (green) in intervertebral disc sections from young versus aged mice; Nuclei are counterstained with DAPI (blue). Scale bar: 100 μm. p Quantification of B2UKX5-positive area (%) in mouse discs. n = 9–10 per group. Data are presented as mean ± SD. Statistical significance was assessed using one-way ANOVA followed by Bonferroni post hoc test, no significant differences were observed in panel f , and Pearson correlation was used for panel k

Article Snippet: Sections were blocked with 10% goat serum before incubation with primary antibodies: COL2 (1:300; GB11021-100, Servicebio), ACAN (1:300; GB11373-100, Servicebio), MMP13 (1:300; GB11247-100, Servicebio), p16 Ink4a (1:200; GB111143-100, Servicebio), IL-6 (1:300; GB11117-100, Servicebio), Akk -EVs-specific antibody (1:50, custom-made, produced by Wuhan FriendBio Technology Co) and B2UKX5-specific antibody (1:50, custom-made, produced by Nanjing GenScript Biotechnology Co).

Techniques: Functional Assay, Expressing, Cell Counting, Control, Staining, Fluorescence

Journal: Bone Research

Article Title: Akkermansia muciniphila attenuates intervertebral disc degeneration via extracellular vesicle-mediated delivery of the effector protein B2UKX5

doi: 10.1038/s41413-026-00541-5

Figure Lengend Snippet: B2UKX5 Supplementation Alleviates IVDD. a Schematic of the experimental protocol for B2UKX5 treatment in tail needle puncture mice. b Representative T2-weighted MRI images of the C8-9 caudal spine. Scale bar: 1 mm. c Statistical analysis of Pfirrmann grading for the C8-9 caudal segment. n = 8 per group. Representative DR images ( d ) and micro-CT 3D reconstruction images ( e ) of the caudal spine. Scale bar: 1 mm. f DHI after 8 weeks of needle puncture at the C8-9 caudal segment. n = 8 per group. Representative H&E ( g ) and SO/FG ( h ) stained images showing the macroscopic morphology of the disc, NP, and AF in the C8-9 segment. Scale bars: 200 μm (Disc) or 50 μm (NP, AF). i Histological scores for the C8-9 segment. n = 8 per group. j Schematic of the experimental protocol for B2UKX5 treatment in naturally aging mice. k Representative T2-weighted MRI images of the lumbar spine in mice following B2UKX5 treatment. Scale bar: 1 mm. l Statistical analysis of the average Pfirrmann grade in the L1-S1 lumbar disc segments. n = 10–16 per group. m Representative micro-CT 3D reconstruction images of the L5-6 lumbar disc segments. Scale bar: 1 mm. n Statistical analysis of the mean DHI in the L2-6 lumbar disc segments. n = 8–9 per group. Representative images of H&E staining ( o ) and SO/FG staining ( p ) showing the macroscopic morphology of intervertebral discs (Disc), nucleus pulposus (NP), annulus fibrosus (AF), and endplate (EP) in the L4-5 lumbar disc segment. Scale bars: 200 μm (Disc) or 50 μm (NP, AF, EP). q Histological scores for each lumbar segment (L2-6). n = 8–9 per group. r Representative IF images showing expression of COL2, ACAN, and MMP13 in the L5-6 lumbar intervertebral disc segment. Scale bar: 200 μm. s Quantitative analysis of IF staining for COL2, ACAN, and MMP13. n = 8–9 per group. Data are presented as mean ± SD. Statistical significance was assessed by one-way ANOVA followed by Bonferroni post hoc test

Article Snippet: Sections were blocked with 10% goat serum before incubation with primary antibodies: COL2 (1:300; GB11021-100, Servicebio), ACAN (1:300; GB11373-100, Servicebio), MMP13 (1:300; GB11247-100, Servicebio), p16 Ink4a (1:200; GB111143-100, Servicebio), IL-6 (1:300; GB11117-100, Servicebio), Akk -EVs-specific antibody (1:50, custom-made, produced by Wuhan FriendBio Technology Co) and B2UKX5-specific antibody (1:50, custom-made, produced by Nanjing GenScript Biotechnology Co).

Techniques: Micro-CT, Staining, Expressing