Dynamics of Wnt/β-catenin reporter activity throughout whole life in a naturally short-lived vertebrate

Wnt/β-catenin signaling plays a major role in regulation of embryogenesis, organogenesis, and adult tissue homeostasis and regeneration. However, the roles played by Wnt/β-catenin and the spatiotemporal regulation of its activity throughout life, including during aging, are not fully understood. To address these issues, we introduced a Wnt/β-catenin signaling sensitive reporter into African turquoise killifish (Nothobranchius furzeri), a naturally ultra-short-lived fish that allows for the analysis of its whole life within a short period of time. Using this reporter killifish, we unraveled the previously unidentified dynamics of Wnt/β-catenin signaling during development and aging. Using the reporter strain, we detected Wnt/β-catenin activity in actively developing tissues as reported in previous reports, but also observed activation and attenuation of Wnt/β-catenin activity during embryonic reaggregation and diapause, respectively. During the aging process, the reporter was activated in the choroidal layer and liver, but its expression decreased in the kidneys. In addition, the reporter also revealed that aging disrupts the spatial regulation and intensity control of Wnt/β-catenin activity seen during fin regeneration, which interferes with precise regeneration. Thus, the employed reporter killifish is a highly useful model for investigating the dynamics of Wnt/β-catenin signaling during both the developmental and aging process.

Divergent selection for opsin gene variation in guppy (Poecilia reticulata) populations of Trinidad and Tobago

The guppy is known to exhibit remarkable interindividual variations in spectral sensitivity of middle to long wavelength-sensitive (M/LWS) cone photoreceptor cells. The guppy has four M/LWS-type opsin genes (LWS-1, LWS-2, LWS-3 and LWS-4) that are considered to be responsible for this sensory variation. However, the allelic variation of the opsin genes, particularly in terms of their absorption spectrum, has not been explored in wild populations. Thus, we examined nucleotide variations in the four M/LWS opsin genes as well as blue-sensitive SWS2-B and ultraviolet-sensitive SWS1 opsin genes for comparison and seven non-opsin nuclear loci as reference genes in 10 guppy populations from various light environments in Trinidad and Tobago. For the first time, we discovered a potential spectral variation (180 Ser/Ala) in LWS-1 that differed at an amino acid site known to affect the absorption spectra of opsins. Based on a coalescent simulation of the nucleotide variation of the reference genes, we showed that the interpopulation genetic differentiation of two opsin genes was significantly larger than the neutral expectation. Furthermore, this genetic differentiation was significantly related to differences in dissolved oxygen (DO) level, and it was not explained by the spatial distance between populations. The DO levels are correlated with eutrophication that possibly affects the color of aquatic environments. These results suggest that the population diversity of opsin genes is significantly driven by natural selection and that the guppy could adapt to various light environments through color vision changes.

Reticulated hyaluronic acid implant in nonperforating trabecular surgery

PURPOSE

To evaluate experimentally and clinically the tolerance and efficacy of a reticulated hyaluronic acid implant in nonperforating trabecular surgery (NPTS).

SETTING

Bascom Palmer Eye Institute, Miami, Florida, USA, and Clinique Sourdille and Clinique Ophtalmologique Universitaire, Nantes, France.

METHODS

In experimental surgery, NPTS was performed with and without a hyaluronic acid implant in 25 rabbit eyes. In a pilot study, the results of NPTS with a hyaluronic acid implant in 72 human eyes were retrospectively analyzed in terms of visual acuity, intraocular pressure (IOP), external filtration, postoperative inflammation, and gonioscopy. Mean follow-up was 13.8 months (range 6 to 24 months).

RESULTS

In the experimental surgery, the rabbit eyes with the implant showed a different healing process than the eyes without the implant. The implant was slowly bioabsorbed and remnants were seen at the operative site (where the tissue was removed) up to day 56 postoperatively. This site was detectable at all histology study periods. Intraocular pressure reduction was longer in the implant group: greater than 5 months versus 3 weeks (P < .05). In the pilot study, visual acuity remained stable, IOP decreased from a mean preoperative level of 26.3 mm Hg +/- 5.22 (SD) to a mean postoperative level without treatment of 15.4 +/- 3.1 mm Hg (P < .0001). No external filtration was detected in 60 eyes, a slightly elevated conjunctiva was noted in 12 eyes. Postoperative inflammation (laser flare and cell measurements) was low. Gonioscopy consistently demonstrated the persistence of a decompression space behind the trabeculum.

CONCLUSION

Comparative experimental surgery results showed excellent tolerance and efficacy in the rabbit eyes with a hyaluronic acid implant. Clinical results, to be confirmed by a randomized comparative study, also showed excellent biocompatibility and encouraging efficacy.

Shared TCR Vbeta gene expression by the pancreas and salivary gland in immunodeficient alymphoplasic mice

Mice with the homozygous mutation alymphoplasia (aly) lack lymph nodes and Peyer's patches and show defects in both humoral and cellular immunity. In these mice, spontaneous infiltration of mononuclear cells was observed in multiple exocrine organs, including the pancreas, salivary glands, and lacrimal glands from the age of 15 wk, progressing to a marked tissue destruction at the age of 25 wk. Using this strain, we examined the phenotypes and TCR Vbeta gene expression of infiltrating T cells to identify the pathologic role of T cell immunity in idiopathic pancreatitis. Most of the infiltrating cells were CD4+ and Thy-1+ cells. Analysis of the TCR gene expression on T cells infiltrating the pancreas and salivary glands showed a high expression of Vbeta1 and Vbeta5 in both organs at the age of 15 wk. In contrast, a diverse expression of TCR Vbeta genes was noted at 25 wk. Sequence analysis of complementarity-determining region 3 (CDR3) of the most prominent TCR Vbeta gene family expressed in these cells, Vbeta1, showed oligoclonal expansion of infiltrating T cells in both organs. Frequent use of glutamine and proline at position 97 was observed in paired tissues. Our data suggest that oligoclonal expansion of organ specific T cells might be one of the etiologic mechanisms of chronic pancreatitis and that common autoantigens could trigger autoimmunity in multiple organs.

Shared TCR Vbeta gene expression by the pancreas and salivary gland in immunodeficient alymphoplasic mice

Mice with the homozygous mutation alymphoplasia (aly) lack lymph nodes and Peyer's patches and show defects in both humoral and cellular immunity. In these mice, spontaneous infiltration of mononuclear cells was observed in multiple exocrine organs, including the pancreas, salivary glands, and lacrimal glands from the age of 15 wk, progressing to a marked tissue destruction at the age of 25 wk. Using this strain, we examined the phenotypes and TCR Vbeta gene expression of infiltrating T cells to identify the pathologic role of T cell immunity in idiopathic pancreatitis. Most of the infiltrating cells were CD4+ and Thy-1+ cells. Analysis of the TCR gene expression on T cells infiltrating the pancreas and salivary glands showed a high expression of Vbeta1 and Vbeta5 in both organs at the age of 15 wk. In contrast, a diverse expression of TCR Vbeta genes was noted at 25 wk. Sequence analysis of complementarity-determining region 3 (CDR3) of the most prominent TCR Vbeta gene family expressed in these cells, Vbeta1, showed oligoclonal expansion of infiltrating T cells in both organs. Frequent use of glutamine and proline at position 97 was observed in paired tissues. Our data suggest that oligoclonal expansion of organ specific T cells might be one of the etiologic mechanisms of chronic pancreatitis and that common autoantigens could trigger autoimmunity in multiple organs.