The heat shock transcription factor (HSF) family consists of three members in mammals and regulates expression of heat shock genes via a heat shock element. HSF1 and HSF2 are required for some developmental processes, but it is unclear how they regulate these processes. To elucidate the mechanisms of developmental regulation by HSFs, we generated mice in which the HSF4 gene is mutated. HSF4‐null mice had cataract with abnormal lens fiber cells containing inclusion‐like structures, probably due to decreased expression of γ‐crystallin, which maintains protein stability. Furthermore, we found increased proliferation and premature differentiation of the mutant lens epithelial cells, which is associated with increased expression of growth factors, FGF‐1, FGF‐4, and FGF‐7. Unexpectedly, HSF1 competed with HSF4 for the expression of FGFs not only in the lens but also in other tissues. These findings reveal the lens‐specific role of HSF4, which activates γ ‐crystallin genes, and also indicate that HSF1 and HSF4 are involved in regulating expression of growth factor genes, which are essential for cell growth and differentiation.

Amniotic membrane transplantation has been reported to be an effective surgical procedure for the reconstruction of the anterior segment of the eye. To understand better the function of transplanted amniotic membrane, we compared the distributions of subchains of type IV collagen and laminin in the amniotic membrane to those in the cornea and conjunctiva. Five human corneas with conjunctivas and three human amniotic membranes were frozen in OCT compound. Cryosections were cut with a cryostat and stained by an indirect immunofluorescent microscopy. We used antibodies of the collagen α2(IV) and α5(IV) subchains, laminin-1, laminin-5, fibronectin, and type VII collagen. In the conjunctival basement membrane and the amniotic membrane, fluorescence was evident for collagen α2(IV) but not for collagen α5(IV). By contrast, in the corneal basement membrane, fluorescence was apparent for the collagen α5(IV) subchain but not for the collagen α2(IV) subchain. Laminin-1, laminin-5, fibronectin, and type VII collagen were present in all the basement membranes examined. The distribution of α subchains of type IV collagen in the amniotic membrane was identical to that in the conjunctiva but different from that in the cornea. No difference in the distribution pattern of other basement membrane components was observed. These results demonstrate that the basement membrane of the amniotic membrane and the conjunctiva might share the same components; therefore, the amniotic membrane might be useful as a replacement for the basement membrane of the conjunctiva.

The therapeutic effects of bacteriophage (phage) KPP12 in Pseudomonas aeruginosa keratitis were investigated in mice. Morphological analysis showed that phage KPP12 is a member of the family Myoviridae, morphotype A1, and DNA sequence analysis revealed that phage KPP12 is similar to PB1-like viruses. Analysis of the phage KPP12 genome did not identify any genes related to drug resistance, pathogenicity or lysogenicity, and so phage KPP12 may be a good candidate for therapeutic. KPP12 showed a broad host range for P. aeruginosa strains isolated from clinical ophthalmic infections. Inoculation of the scarified cornea with P. aeruginosa caused severe keratitis and eventual corneal perforation. Subsequent single-dose administration of KPP12 eye-drops significantly improved disease outcome, and preserved the structural integrity and transparency of the infected cornea. KPP12 treatment resulted in the suppression of neutrophil infiltration and greatly enhanced bacterial clearance in the infected cornea. These results indicate that bacteriophage eye-drops may be a novel adjunctive or alternative therapeutic agent for the treatment of infectious keratitis secondary to antibiotic-resistant bacteria.

Background Disruption of corneal epithelial barrier function by inflammation may contribute to the development of dry eye. The effects of rebamipide, a drug used for the treatment of dry eye, on barrier function and cytokine expression in a human corneal epithelial (HCE) cell line were examined. Methods Barrier function of HCE cells was evaluated by measurement of transepithelial electrical resistance (TER). The subcellular localisation of the tight junction protein zonula occludens (ZO)-1 was examined by immunofluorescence analysis. The release of cytokines was determined with ELISAs, and the intracellular abundance of cytokine mRNAs was quantitated by reverse transcription and real-time PCR analysis. Degradation of the nuclear factor-κB inhibitor IκBα was detected by immunoblot analysis. Results Rebamipide increased TER of HCE cells in a concentration-dependent manner as well as attenuating the loss of TER and the disappearance of ZO-1 from the cell surface induced by tumour necrosis factor α (TNFα). Rebamipide also suppressed TNFα-induced expression of interleukin-6 and interleukin-8 at the mRNA and protein levels and inhibited the TNFα-induced degradation of IκBα. Conclusions The upregulation of barrier function and the anti-inflammatory effects of rebamipide, together with its mucin secretagogue activity, may contribute to the effectiveness of this drug for the treatment of dry eye.