Fig 2: Congenital nuclear cataract occurs in Jamc−/− mice. (A) Slit-lamp view demonstrating transparent lens in WT mice and severe lens opacity in Jamc−/− mice (P21). (B) Representative darkfield images of lenses in WT and Jamc−/− mice (P21) showing nuclear cataract and smaller size in the Jamc−/− lenses. Scale bar: 500 µm. (C) Viability and cataract incidence of offspring (61 litters) at P7. Cataracts were detected with 100% incidence only in Jamc−/− mice.

Fig 3: Schematic model for the regulation of ADSC functions by soluble JAM-C. The soluble JAM-C (sJAM-C) deposited on the extracellular matrix interacts with JAM-B and partly with JAM-C on ADSC. sJAM-C/JAM-B signaling reaches the nucleus (dashed arrow) and stimulates cellular proliferation and expression of MSC markers (arrows). MSC, mesenchymal stromal/stem cell.

Fig 4: JAM-C is widely distributed in the fat interstitial tissues. (A–C) Confocal images of mouse ADSCs stained for the indicated markers. Asterisks indicate lipid droplets in differentiated adipocytes, and arrowheads show colocalization of JAM-C and ether type III collagen or heparan sulfate proteoglycan (HSPG). Squares show the enlarged areas. Scale bars, 50 µm.

Fig 5: JAM-C knockout mice and the expression of JAM-C in WT and Jamc-/- mouse lenses. (A) Schematic diagram of the generation of JAM-C knockout mice. Two loxP sites (red triangles) were inserted to flank the promoter region and exon 1 (gray box 1) of Jamc. The epitope of the JAM-C antibody corresponds to the coding region between exon 2 and exon 7. Primers used for PCR genotyping are indicated by blue arrows. Primers used for qPCR to validate JAM-C deletion are indicated by gray arrows. (B) Real-time PCR normalized to ß-actin revealed that the mRNA expression of JAMC in WT mouse lenses showed no significant differences among the ages of 1 day, 7 days, 14 days, and 6 weeks. The graph is presented as mean ± SEM. NS, not significant; n = 3. (C) The mRNA expression of JAM-C was determined by real-time PCR, normalized to ß-actin in P21 WT and Jamc-/- lenses, and then quantified. The mRNA expression of Jamc shows a nearly complete knockout in Jamc-/- lenses. ****P < 0.0001; n = 3. (D) Proteins were extracted from WT and Jamc-/- mice lenses at P14 and then probed for JAM-C expression by western blot; a-tubulin was used as a loading control. The protein expression of JAM-C indicates nearly complete knockout of JAM-C in Jamc-/- lenses. (E) Representative immunofluorescent staining images of WT and Jamc-/- lenses in cryosections for JAM-C (red) and DAPI-stained nuclei (blue). JAM-C mainly localized on lens epithelium in E14.5 and P1 WT lenses. In P7 WT lenses, JAM-C stains were found in the lens epithelium and cortical lens fiber of WT mice but not in Jamc-/- mice. (Right) Higher magnifications of boxed areas. Scale bar: 200 µm.