High Ambient Temperature Accelerates Leaf Senescence via PHYTOCHROME-INTERACTING FACTOR 4 and 5 in Arabidopsis.

Leaf senescence is a developmental process by which a plant actively remobilizes nutrients from aged and photosynthetically inefficient leaves to young growing ones by disassembling organelles and degrading macromolecules. Senescence is accelerated by age and environmental stresses such as prolonged darkness. Phytochrome B (phyB) inhibits leaf senescence by inhibiting phytochrome-interacting factor 4 (PIF4) and PIF5 in prolonged darkness. However, it remains unknown whether phyB mediates the temperature signal that regulates leaf senescence. We found the light-activated form of phyB (Pfr) remains active at least four days after a transfer to darkness at 20°C but is inactivated more rapidly at 28°C. This faster inactivation of Pfr further increases PIF4 protein levels at the higher ambient temperature. In addition, PIF4 mRNA levels rise faster after the transfer to darkness at high ambient temperature via a mechanism that depends on ELF3 but not phyB. Increased PIF4 protein then binds to the ORE1 promoter and activates its expression together with ABA and ethylene signaling, accelerating leaf senescence at high ambient temperature. Our results support a role for the phy-PIF signaling module in integrating not only light signaling but also temperature signaling in the regulation of leaf senescence.

Concurrent activation of OsAMT1;2 and OsGOGAT1 in rice leads to enhanced nitrogen use efficiency under nitrogen limitation.

Nitrogen (N) is a major factor for plant development and productivity. However, the application of nitrogenous fertilizers generates environmental and economic problems. To cope with the increasing global food demand, the development of rice varieties with high nitrogen use efficiency (NUE) is indispensable for reducing environmental issues and achieving sustainable agriculture. Here, we report that the concomitant activation of the rice (Oryza sativa) Ammonium transporter 1;2 (OsAMT1;2) and Glutamate synthetase 1 (OsGOGAT1) genes leads to increased tolerance to nitrogen limitation and to better ammonium uptake and N remobilization at the whole plant level. We show that the double activation of OsAMT1;2 and OsGOGAT1 increases plant performance in agriculture, providing better N grain filling without yield penalty under paddy field conditions, as well as better grain yield and N content when plants are grown under N llimitations in field conditions. Combining OsAMT1;2 and OsGOGAT1 activation provides a good breeding strategy for improving plant growth, nitrogen use efficiency and grain productivity, especially under nitrogen limitation, through the enhancement of both nitrogen uptake and assimilation.

Molecular bases for differential aging programs between flag and second leaves during grain-filling in rice.

Flag leaves (FL) and second leaves (SL) in rice show differential aging patterns during monocarpic senescence. Coordination of aging programs between FL and SL is important for grain yield and quality. However, the molecular bases for differential aging programs between FL and SL have not been systematically explored in rice. Here, we performed mRNA-sequencing of FL and SL at six time points during grain-filling and identified four molecular bases for differential aging programs between FL and SL: phenylpropanoid biosynthesis, photosynthesis, amino acid (AA) transport, and hormone response. Of them, photosynthesis (carbon assimilation) and AA transport (nitrogen remobilization) predominantly occurred in FL and SL, respectively, during grain-filling. Unlike other molecular bases, AA transport showed consistent differential expression patterns between FL and SL in independent samples. Moreover, long-distance AA transporters showed invariant differential expression patterns between FL and SL after panicle removal, which was consistent to invariant differential nitrogen contents between FL and SL after panicle removal. Therefore, our results suggest that the supplies of carbon and nitrogen to seeds is functionally segregated between FL and SL and that long-distance AA transport is an invariant core program for high nitrogen remobilization in SL.

Advantages of the phosphatidylserine-recognizing peptide PSP1 for molecular imaging of tumor apoptosis compared with annexin V.

A number of peptide-based indicators have been identified and reported as potential apoptosis probes, offering great promise for early assessment of therapeutic efficacy in several types of cancer. Direct comparison of the newly developed probes with previously used ones would be an important step in assessing possible applications. Here, we compared the newly identified peptide-based phosphatidylserine (PS) indicator PSP1 (CLSYYPSYC) with annexin V, a common probe for molecular imaging of apoptotic cells, with respect to PS binding kinetics, apoptotic cell-targeting ability, and the efficacy of homing to apoptotic tumor cells in a mouse model after treatment with the anticancer agent camptothecin. Our results indicate that PSP1 efficiently targeted apoptotic cells and generated apoptosis/tumor-specific signals after cancer treatment in the animal model, whereas a similar dose of annexin V showed weak signals. The formation of a stable complex of PSP1 with PS might be one reason for the efficient in vivo targeting. We suggest that PSP1 has potential advantages for in vivo apoptotic cell imaging and could serve as a platform for the development of de novo peptide-based probes for apoptosis.

Construction and application of elastin like polypeptide containing IL-4 receptor targeting peptide.

Various human solid tumors highly express IL-4 receptors which amplify the expression of some of anti-apoptotic proteins, preventing drug-induced cancer cell death. Thus, IL-4 receptor targeted drug delivery can possibly increase the therapeutic efficacy in cancer treatment. Macromolecular carriers with multivalent targeting moieties offered great advantages in cancer therapy as they not only increase the plasma half-life of the drug but also allow delivery of therapeutic drugs to the cancer cells with higher specificity, minimizing the deleterious effects of the drug on normal cells. In this study we designed a library of elastin like polypeptide (ELP) polymers containing tumor targeting AP1 peptide using recursive directional ligation method. AP1 was previously discovered as an atherosclerotic plaque and breast tumor tissue homing peptide using phage display screening method, and it can selectively bind to the interleukin 4 receptor (IL-4R). The fluorescently labeled [AP1-V12]6, an ELP polymer containing six AP1 enhanced tumor-specific targeting ability and uptake efficiency in H226 and MDA-MB-231 cancer cell lines in vitro. Surface plasmon resonance analysis showed that multivalent presentation of the targeting ligand in the ELP polymer increased the binding affinity towards IL-4 receptor compared to free peptide. The binding of [AP1-V12]6 to cancer cells was remarkably reduced when IL-4 receptors were blocked by antibody against IL-4 receptor further confirmed its binding. Importantly, the Cy5.5-labeled [AP1-V12]6 demonstrated excellent homing and longer retention in tumor tissues in MDA-MB-231 xenograft mouse model. Immunohistological studies of tumor tissues further validated the targeting efficiency of [AP1-V12]6 to tumor tissue. These results indicate that designed [AP1-V12]6 can serve as a novel carrier for selective delivery of therapeutic drugs to tumors.

Designed nanocage displaying ligand-specific Peptide bunches for high affinity and biological activity.

Protein-cage nanoparticles are promising multifunctional platforms for targeted delivery of imaging and therapeutic agents owing to their biocompatibility, biodegradability, and low toxicity. The major advantage of protein-cage nanoparticles is the ability to decorate their surfaces with multiple functionalities through genetic and chemical modification to achieve desired properties for therapeutic and/or diagnostic purposes. Specific peptides identified by phage display can be genetically fused onto the surface of cage proteins to promote the association of nanoparticles with a particular cell type or tissue. Upon symmetrical assembly of the cage, peptides are clustered on the surface of the cage protein in bunches. The resulting PBNC (peptide bunches on nanocage) offers the potential of synergistically increasing the avidity of the peptide ligands, thereby enhancing their blocking ability for therapeutic purposes. Here, we demonstrated a proof-of-principle of PBNCs, fusing the interleukin-4 receptor (IL-4R)-targeting peptide, AP-1, identified previously by phage display, with ferritin-L-chain (FTL), which undergoes 24-subunit assembly to form highly stable AP-1-containing nanocage proteins (AP1-PBNCs). AP1-PBNCs bound specifically to the IL-4R-expressing cell line, A549, and their binding and internalization were specifically blocked by anti-IL-4R antibody. AP1-PBNCs exhibited dramatically enhanced binding avidity to IL-4R compared with AP-1 peptide, measured by surface plasmon resonance spectroscopy. Furthermore, treatment with AP1-PBNCs in a murine model of experimental asthma diminished airway hyper-responsiveness and eosinophilic airway inflammation along with decreased mucus hyperproduction. These findings hold great promise for the application of various PBNCs with ligand-specific peptides in therapeutics for different diseases, such as cancer.

New proposal for the treatment of viral warts with intralesional injection of 5-aminolevulinic acid photodynamic therapy.

BACKGROUND: Although photodynamic therapy (PDT) using intralesional injection (ILI) can theoretically enhance the efficacy of the PDT, the effect of ILI-PDT on warts has not been reported in the literature so far. METHODS: Eight patients with multiple viral warts were enrolled in the study. PDT was performed after the incubation for 1 h, followed by the ILI of aminolevulinic acid (ALA) into the warts. The treatment was repeated at 2-3 week intervals. RESULTS: Fifty percent of patients showed good to cure response. Complete remission was observed in two patients. There was no apparent correlation between the initial severity of warts and the likelihood of response. No one reported severe adverse reaction. CONCLUSIONS: The present study suggests that intralesional administration of ALA might be a safe and effective treatment option of thick treatment-resistant warts and can be performed with a shorter incubation period.

Prevalence of atopic dermatitis among Korean adults visiting health service center of the Catholic Medical Center in Seoul Metropolitan Area, Korea.

The point prevalence of atopic dermatitis (AD) among Korean adults visiting the Health Service Center for health check-ups was assessed. AD was diagnosed based on the questionnaires filled by patients and through physical examination by dermatologists. A total of 3,563 persons completed the questionnaires, and 2,032 persons were examined by the dermatologists. According to the questionnaires, the prevalence of AD was 7.1%, and from the dermatologists' examination, it was 2.6% overall, which decreased with age significantly. The prevalence in men was higher than that of women. Grading the severity of AD according to their eczema area and severity index scores, 70.6% were classified as being mild, 25.5% moderate, and 3.9% severe. Interestingly, concomitance of psoriasis and AD was found in 0.5% of those examined by the dermatologists. Our results suggest that AD is one of the most common skin diseases not only in children but also in adults in Korea.

Clinicopathologic characteristics of cutaneous chronic graft-versus-host diseases: a retrospective study in Korean patients.

BACKGROUND: Chronic graft-versus-host disease (cGVHD) is a major complication in long-term survivors of hematopoietic stem cell transplantation (HSCT). Cutaneous manifestations are frequently the presenting features; therefore, the dermatologist needs to be aware of the wide spectrum of cutaneous cGVHD. METHODS: We retrospectively evaluated patients' characteristics, clinical, and histological features of cutaneous cGVHD and analyzed factors influencing the severity of cutaneous cGVHD in 100 Korean HSCT recipients between January 1, 1995, and December 31, 2007. RESULTS: Clinical manifestations of cutaneous cGVHD mainly presented as lichenoid (60.0%), sclerodermoid (12.0%), or erythematous maculopapular (22.0%) patterns. Other less common findings included xerosis, dyspigmentation, acquired ichthyosis, eczema, exfoliative dermatitis, alopecia, erythema multiforme-like or keratosis pilaris-like eruption. Among 100 patients, 46 patients were investigated for nail involvement, and 29 (63.0%) of them were accompanied with nail abnormalities. Histologically, characteristic lichenoid lesions were observed in 53%, sclerodermoid in 9%, and acute/chronic overlap syndrome in 28% of patients. We also discovered that HSCT from female donors to male recipients increased the severity of cutaneous cGVHD. CONCLUSIONS: We report a large study about cutaneous cGVHD in Asian patients. Cutaneous cGVHD presented with a wide spectrum of clinical and histological manifestations.

A case of steatocystoma multiplex limited to the scalp.

We report here on a 63-year-old woman who had several small, yellowish papules on the scalp for the previous 2 years. There was no family history of similar lesions. Yellowish, creamy material was expressed from a papule during punch biopsy. Histologic examination from the lesion revealed the typical features of steatocystoma multiplex. We report here on this rare variant of steatocystoma multiplex that was limited to the scalp.

A Case of Amelanotic Subungual Melanoma.

Amelanotic subungual melanoma is a rare dermatosis, and it is frequently misdiagnosed probably because of its nonspecific clinical features. We herein report on a case of amelanotic subungual melanoma extended to the adjacent skin in a 36-year-old Korean woman. This case is interesting in that clinically, it needed differentiation from Bowen's disease, lichen planus, sarcoidosis, etc. and very early invading features of the melanoma were observed on the histopathologic section.